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1

An anechoic chamber facility for investigating aerodynamic noise  

NASA Technical Reports Server (NTRS)

The aerodynamic noise facility was designed to be used primarily for investigating the noise-generating mechanisms of high-temperature supersonic and subsonic jets. The facility consists of an anechoic chamber, an exhaust jet silencer, instrumentation equipment, and an air heater with associated fuel and cooling systems. Compressed air, when needed for jet noise studies, is provided by the wind tunnel compressor facility on a continuous basis. The chamber is 8.1 m long, 5.0 m wide, and 3.0 m high. Provisions have been made for allowing outside air to be drawn into the anechoic chamber in order to replenish the air that is entrained by the jet as it flows through the chamber. Also, openings are provided in the walls and in the ceiling for the purpose of acquiring optical measurements. Calibration of the chamber for noise reflections from the wall was accomplished in octave bands between 31.2 Hz and 32 kHz.

Massier, P. F.; Parthasarathy, S. P.

1972-01-01

2

Anechoic chamber wideband antenna measurements  

Microsoft Academic Search

The method is considered which consists of measurements of output antenna signals on a number of frequencies and Fourier transformation of data into time domain for separation of own antenna field and interference fields. The results of testing at serial facility for antenna measurements in an anechoic chamber are presented as for diagnosis of scattered fields, as for improvement of

A. V. Kalinin

2006-01-01

3

Experimental evaluation of anechoic chambers  

Microsoft Academic Search

Antenna gain and radiation patterns, as well as radar cross sections of objects are measured in anechoic chambers. The chambers are used for convenience and to eliminate, as far as practical, sources of unwanted reflections. It would be useful if anechoic chambers could be categorized by a figure of merit which would predict their performance when antenna measurements are made.

W. Kummer; A. Villeneuve

1965-01-01

4

Anechoic chamber qualification at ultrasonic frequencies  

NASA Astrophysics Data System (ADS)

Qualifying an anechoic chamber for frequencies that extend into the ultrasonic range is necessary for research work involving airborne ultrasonic sound. For example, an anechoic chamber allows for measurements of the direct sound radiated by an object without reflections from walls. The ANSI S12.55/ISO 3745 standard which covers anechoic chamber qualification does not extend into the ultrasonic frequency range, nor have others discussed this frequency range in the literature. An increasing number of technologies are employing ultrasound; hence the need to develop facilities to conduct basic research studies on airborne ultrasound. This presentation will discuss the challenges associated with chamber qualification and present the results for qualification of a chamber at Brigham Young University. [This work has been funded by the Los Alamos National Laboratory

Jenny, Trevor; Anderson, Brian

2010-10-01

5

Preliminary development of mini anechoic chamber  

Microsoft Academic Search

The purpose of mini anechoic chamber is to allow cost effective testing of microwave signal. It is because measurements of the radiation pattern are usually done in an anechoic chamber in order to avoid reflections from nearby objects and external interference from affecting the field pattern. The most important element in anechoic chamber is absorber. The electromagnetic wave absorbers are

A. Hasnain; M. I. Imran; Z. S. Rohaiza; S. Roslan; A. A. Takiyuddin; A. Rusnani; A. A. Azremi

2007-01-01

6

Synthesizing realistic environments in an anechoic chamber  

Microsoft Academic Search

We present an experimental setup in anechoic chamber that synthesizes realistic frequency selective fading properties. Antennas for S-band mobile TV applications are tested in that synthesized environment.

L. Rudant; C. Delaveaud; M. AbouElAnouar

2009-01-01

7

Characteristics of a tapered anechoic chamber  

Microsoft Academic Search

The characteristic features of a tapered anechoic chamber are described. The smooth illumination amplitude in the chamber makes it usable as an indoor range for antenna pattern measurements, even at low frequencies. Variations in the transmission attenuation in the chamber as compared to free space require careful interpretation of absolute gain and cross section data.

H. King; F. Shimabukuro; J. Wong

1967-01-01

8

Almond test body. [for microwave anechoic chambers  

NASA Technical Reports Server (NTRS)

The invention is an almond shaped test body for use in measuring the performance characteristics of microwave anechoic chambers and for use as a support for components undergoing radar cross-section measurements. The novel aspect of this invention is its shape, which produces a large dynamic scattered field over large angular regions making the almond valuable for verifying the performance of microwave anechoic chambers. As a component mount, the almond exhibits a low return that does not perturb the measurement of the component and it simulates the backscatter characteristics of the component as if over an infinite ground plane.

Dominek, Allen K. (inventor); Wood, Richard M. (inventor); Gilreath, Melvin C. (inventor)

1989-01-01

9

ABSORBER FOAM CHARACTERIZATION FOR PREDICTING OVERALL ANECHOIC CHAMBER PERFORMANCE  

E-print Network

ABSORBER FOAM CHARACTERIZATION FOR PREDICTING OVERALL ANECHOIC CHAMBER PERFORMANCE Christopher R University 1 Grand Avenue, San Luis Obispo, CA 93407 ABSTRACT A new rectangular anechoic chamber (20'L x 10'W indicative of the foam geometry. The measured data are subsequently used to predict overall anechoic chamber

Arakaki, Dean Y.

10

AIAA 2004-0010 Designing an Anechoic Chamber for  

E-print Network

AIAA 2004-0010 Designing an Anechoic Chamber for the Experimental Study of High Speed Heated Jets 500, Reston, VA 20191­4344 #12;AIAA 2004-0010 Designing an Anechoic Chamber for the Experimental Study & S Engineers, Inc. Syracuse, NY 13212 The refurbishment of the 7, 300ft3 anechoic chamber located at Syracuse

Tinney, Charles E.

11

Modeling semi-anechoic electromagnetic measurement chambers  

Microsoft Academic Search

Previous studies developed a model to predict theoretically the low-frequency plane-wave reflection coefficient of an array of pyramid cone absorbers such as those used to line anechoic electromagnetic measurement chambers. The present authors apply this model in a geometrical optics approach to predict the electromagnetic field in a chamber lined with cone absorbers in the frequency range of 30-300 MHz.

Christopher L. Holloway; Edward F. Kuester

1996-01-01

12

Upgrade of foam equipped semi anechoic chambers to fully anechoic chambers by the use of ferrite tiles  

Microsoft Academic Search

Different standard boards are developing EMC standards that allow a fully anechoic chamber being used for radiated EMC testing. In this paper an investigation is done on foam equipped semi anechoic chambers, that do not fulfil the requirements to become accredited for EMC emission testing. Additional absorbers are mounted on the ground plane to change the chambers to fully anechoic

J. Haala; W. Wiesbeck

1998-01-01

13

Antenna diversity measurement system in anechoic chamber  

Microsoft Academic Search

This paper presents theoretical and experimental results to demonstrate the capabilities of an antenna-diversity measurement set-up installed in an anechoic chamber. A numerical model of the set-up has been developed and provides theoretical results on the accuracy and limitations of the system. Experimental tests have been performed with dipole antennas in space-diversity with good agreement with the simulations.

L. Dussopt; L. Descroix

2009-01-01

14

Reflectivity level of radio anechoic chambers  

Microsoft Academic Search

A comparison between the antenna-pattern comparison technique and the free-space voltage standing-wave ratio technique for evaluating the reflectivity level of radio anechoic chambers is presented. Based on an analysis of the two techniques, it is pointed out which parameters influence the measured value of the reflectivity level. The comparison is illustrated with experimental results and it is explained why inconsistent

J. Appel-Hansen

1973-01-01

15

Radiated Immunity Tests: Reverberation Chamber vs. Anechoic Chamber Results  

Microsoft Academic Search

The paper concerns the comparison between reverberation chamber measurements (RC) and anechoic chamber (AC) measurements: in particular, the case of an immunity test is considered. A two-wire transmission line is adopted as a device under test (DUT), and the current induced on the line by the external field is monitored to construct a possible susceptibility profile. Both the averaged current,

Roberto De Leo; Valter Mariani Primiani

2005-01-01

16

Radiated immunity tests: reverberation chamber versus anechoic chamber results  

Microsoft Academic Search

This paper concerns the comparison between reverberation chamber (RC) and anechoic chamber (AC) measurements: In particular, the case of an immunity test is considered. A two-wire transmission line is adopted as a device under test (DUT), and the current induced on the line by the external field is monitored to construct a possible susceptibility profile. Both the averaged current over

Roberto De Leo; Valter Mariani Primiani

2006-01-01

17

REFLECTIVITY CHARACTERIZATION AND IDENTIFICATION OF PRIMARY REFLECTION PATH IN ANECHOIC CHAMBER ANALYSIS  

E-print Network

REFLECTIVITY CHARACTERIZATION AND IDENTIFICATION OF PRIMARY REFLECTION PATH IN ANECHOIC CHAMBER ABSTRACT This paper presents an analysis of the reflectivity performance of the anechoic chamber Chamber, Chamber Reflectivity, Quiet Zone, Ray Tracing, Interferometer Analysis 1. Introduction Anechoic

Arakaki, Dean Y.

18

Anechoic chamber design using ray tracing and theory of images  

Microsoft Academic Search

A ray-tracing technique which was used to help find the best possible anechoic chamber design in the frequency range of 30 MHz to 300 MHz is discussed. The electromagnetic fields due to a source inside the chamber are calculated. The scattered field is compared to the free space field to calculate the performance of the anechoic chamber in free space.

M. K. Mansour; J. Jarem

1990-01-01

19

A low cost conversion of semi-anechoic chamber to fully-anechoic chamber for RF antenna measurements  

Microsoft Academic Search

The commonly use of semi-anechoic chambers (SAC) is for electromagnetic interference emission (EMI) measurements. This paper suggests a simple technique to extend the EMI chamber capability to a low-cost fully anechoic chamber (FAC) to characterize the antenna performance. The dimensions of the absorbing cones placed o the reflecting ground surface are based on the Fresnel's zone concept. The receiving antenna

C. Kinezos; Vichate Ungvichian

2003-01-01

20

Anechoic chamber evaluation using the matrix pencil method  

Microsoft Academic Search

A new method for evaluation of an anechoic chamber using the matrix pencil method is presented. A signal measured between two antennas placed in an anechoic chamber is sliced into small frequency intervals and is processed using the matrix pencil method. In each interval, the measured signal is decomposed into its propagating-wave components, which correspond to a direct propagation between

B. Fourestie; Z. Altman; M. Kanda

1999-01-01

21

MODELING OF ANECHOIC CHAMBER USING A BEAM-TRACING TECHNIQUE  

Microsoft Academic Search

Abstract—Building an anechoic chamber,involves a substantial investment both financially and in physical space. Hence, there is much interest in trying to reduce the required investment while still maintaining adequate performance. The performance of an anechoic chamber depends on the type, size, and array configuration of the absorber elements as well as the geometry of the screened room on which the

Boon-Kuan Chung; C. H. Teh; Hean-Teik Chuah

2004-01-01

22

TEM wave propagation in a parallel, four wire anechoic chamber enclosure  

Microsoft Academic Search

Propagation of a TEM wave in a four-wire anechoic chamber facility is considered. The electromagnetic fields of the four-wire system are given when anechoic chamber material is and is not present. The analysis of this problem is divided into two main parts: the first part analyzes how a TEM wire propagates in a four-wire system that is surrounded by four

John M. Jarem

1989-01-01

23

Time-domain modeling, characterization, and measurements of anechoic and semi-anechoic electromagnetic test chambers  

Microsoft Academic Search

We present time-domain techniques for modeling, characterizing, and measuring anechoic and semi-anechoic chambers used for emission and immunity testing of digital devices. The finite difference time-domain (FDTD) approach is used to model and characterize these chambers. In the FDTD model presented here, we discuss methods used to eliminate the need to spatially resolve the fine detail of the absorbing structures;

Christopher L. Holloway; Paul M. McKenna; Roger A. Dalke; Rodney A. Perala; Charles L. Devor

2002-01-01

24

Characteristics of an anechoic chamber for fan noise testing  

NASA Technical Reports Server (NTRS)

Acoustical and mechanical design features of NASA Lewis Research Center's engine fan noise facility are described. Acoustic evaluation of the 1420-m (50,000-ft) chamber, which is lined with an array of stepped wedges, is described. Results from the evaluation in terms of cut-off frequency and non-anechoic areas near the walls are detailed. Fan models with 0.51-m (20-in) diameters are electrically driven to 20,600 rpm in either the inlet mode (drawing air from the chamber) or exhaust mode (discharging air into the chamber) to facilitate study of both fore and aft fan noise. Inlet noise characteristics of the first fan tested, the JT8D Refan, are discussed and compared to full-scale levels. Turbulence properties of the inlet flow and acoustic results are compared with and without a turbulence reducing screen over the fan inlet.

Wazyniak, J. A.; Shaw, L. M.; Essary, J. D.

1977-01-01

25

Anechoic Chambers: Aerospace Applications. (Latest Citations from the Aerospace Database)  

NASA Technical Reports Server (NTRS)

The bibliography contains citations concerning the design, development, performance, and applications of anechoic chambers in the aerospace industry. Anechoic chamber testing equipment, techniques for evaluation of aerodynamic noise, microwave and radio antennas, and other acoustic measurement devices are considered. Shock wave studies on aircraft models and components, electromagnetic measurements, jet flow studies, and antenna radiation pattern measurements for industrial and military aerospace equipment are discussed. (Contains 50-250 citations and includes a subject term index and title list.)

1996-01-01

26

Anechoic Chambers: Aerospace Applications. (Latest Citations from the Aerospace Database)  

NASA Technical Reports Server (NTRS)

The bibliography contains citations concerning the design, development, performance, and applications of anechoic chambers in the aerospace industry. Anechoic chamber testing equipment, techniques for evaluation of aerodynamic noise, microwave and radio antennas, and other acoustic measurement devices are considered. Shock wave studies on aircraft models and components, electromagnetic measurements, jet flow studies, and antenna radiation pattern measurements for industrial and military aerospace equipment are discussed. (Contains 50-250 citations and includes a subject term index and title list.)

1995-01-01

27

Characterisation of electromagnetic anechoic chamber by finite element method  

Microsoft Academic Search

A finite element solver for the complex electric field vector has been used to characterise an anechoic chamber. The chamber walls are lined with ferrite tiles and the absorbing boundary condition has been modified to model the tile as a surface impedance. The chamber has also been characterised experimentally so that a full comparison of results has been possible in

A. E. Baker; R. M. Sitzia; I. Preston; A. Puzo; A. Pons

1996-01-01

28

View of antenna test activity in Anechoic Chamber, bldg 14  

NASA Technical Reports Server (NTRS)

View of antenna test activity in the Anechoic Chamber, bldg 14, JSC. The chamber walls are completely covered with foam pyramids for absorbing stray radiation during spacecraft antenna radiation pattern tests. The subject, in a extravehicular mobility units (EMU) is perched atop the maneuverable tower lift, which is part of the test set up for lunar surface extravehicular activity (EVA) antenna studies.

1966-01-01

29

Numerical analysis and optimization of anechoic chambers for EMC testing  

Microsoft Academic Search

Anechoic chambers for EMC testing in the frequency range from 30 MHz to 1 GHz have to fulfil stringent requirements before they are accepted for standardized emission and immunity measurements. In Europe, these requirements will lead to the exclusion of about 90% of the existing and 50% of the new chambers from accreditation due to the formerly lower standards. This

Christian Bornkessel; Wemer Wiesbeck

1996-01-01

30

Design and construction of a multipurpose wideband anechoic chamber  

Microsoft Academic Search

An electromagnetic anechoic chamber has been constructed at the Multimedia University. It is designed to operate over a very wide frequency range from 30 MHz through 18 GHz. It can be used for electromagnetic compatibility (EMC) tests, antenna measurements, radar cross section (RCS) measurements, testing RF transceivers, calibration of scatterometers, and other electromagnetic research experiments. The geometry of the chamber

B. K. Chung; H. T. Chuah

2003-01-01

31

Electromagnetic field analysis of a four-wire anechoic chamber  

Microsoft Academic Search

The electromagnetic field characteristics and plane-wave generating ability of a parallel four-wire anechoic chamber which is to be operated in the VHF range is analyzed. The analysis considers three cases: the first is a four-wire chamber when only a thin layer of absorber material covers the chamber walls, the second is a four-wire chamber when only free space surrounds the

JOHN M. JAREM

1990-01-01

32

Characteristics of an anechoic chamber for fan noise testing  

NASA Technical Reports Server (NTRS)

Acoustical and mechanical design features of NASA Lewis Research Center's engine fan noise facility are described. Acoustic evaluation of the chamber, which is lined with an array of stepped wedges, is described. Results from the evaluation in terms of cut-off frequency and non-anechoic areas near the walls are detailed. Fan models are electrically driven to 20,600 RPM in either the inlet mode or exhaust mode to facilitate study of both fore and aft fan noise. Inlet noise characteristics of the first fan tested are discussed and compared to full-scale levels. Turbulence properties of the inlet flow and acoustic results are compared with and without a turbulence reducing screen over the fan inlet.

Wuzyniak, J. A.; Shaw, L. M.; Essary, J. D.

1977-01-01

33

Comparison of anechoic and reverberation chamber coupling data as a function of directivity pattern  

Microsoft Academic Search

This paper compares coupling data from an external field to an internal probe for anechoic and reverberation chamber tests as a function of the directivity pattern of a test article and the test conditions for both chambers. The investigation uses an extensive measurement data base from both anechoic and reverberation chambers. In an ideal anechoic chamber test, the test article

Gustav J. Freyer; M. G. Backstrom

2000-01-01

34

A microwave anechoic chamber for radar-cross section measurement  

Microsoft Academic Search

A microwave anechoic chamber has been developed at the Department of Electrical Engineering, University of Malaya, for monostatic and bistatic radar-cross-section measurements. The structure of the chamber is a quarter-section geodesic dome, with a 12 foot radius, and raised three feet above the floor. An antenna railing system is installed inside the chamber. The antennas can be moved along the

B. K. Chung; H. T. Chuah; J. W. Bredow

1997-01-01

35

Correcting OATS antenna factors for small fully anechoic chambers  

Microsoft Academic Search

Antenna correction factors have been experimentally determined inside a 3 m fully anechoic chamber. In the frequency range of 30-1000 MHz deviations to the manufacturer data, taken from a 10 m OATS, of up to 5 dB have been found in the low frequency range. In the high frequency range the calibration for horizontal polarization was strongly affected, in a

Diethard Hansen; Detlef Ristau; Peter Lilienkamp

2000-01-01

36

EXPERIMENTAL ANECHOIC CHAMBER MEASUREMENTS OF A TARGET NEAR AN INTERFACE  

Microsoft Academic Search

Abstract—The backscattered field of an illuminated sphere with diameter ? =3 0.5 cm above a perfect conducting plate is measured in an anechoic chamber,at different heights for a varying incidence angle ? in the range 5,. A high frequency field ? ? ? is transmitted,so that two significant transitions from lit to shadow regions are given over the entire incidence

Nicolas P. Marquart

2006-01-01

37

Finite Element Analysis Of Wedges Used In Anechoic Chambers  

Microsoft Academic Search

Wedges are often used in lining the internal surfaces of the anechoic chambers. The design of these wedges has invariably been based on extensive experimentation. In this paper, a finite element model for predicting the reflection characteristics of a wedge in an impedance tube is proposed. This model is based on the bulk reaction concept, thus accounting for the wave

V. Easwaran; M. L. Munjal

1993-01-01

38

Apparent distance of sounds recorded in echoic and anechoic chambers  

Microsoft Academic Search

With miniature microphones inserted into the external ear canals of a model and the sound source 90° to left of midline, low-pass, and high-pass, broadband noise bursts were picked up and recorded on magnetic tape. The bursts were generated in 2 highly contrasting acoustic environments: an anechoic and an echoic chamber. The taped sounds were played back monaurally and binaurally

Robert A. Butler; Elena T. Levy; William D. Neff

1980-01-01

39

ANALYSIS OF ANECHOIC CHAMBER TESTING OF THE HURRICANE IMAGING RADIOMETER  

E-print Network

ANALYSIS OF ANECHOIC CHAMBER TESTING OF THE HURRICANE IMAGING RADIOMETER David Fenigstein1 , Chris Sparkman Drive Huntsville, AL 35805 Abstract ­ The Hurricane Imaging Radiometer System (HIRAD) is a new algorithm. Keywords-microwave radiometer, synthetic aperture radiometry, image reconstruction I

Ruf, Christopher

40

Figure of merit for low frequency anechoic chambers based on absorber reflection coefficients  

Microsoft Academic Search

Return loss as a function of frequency and angle of incidence is studied to determine the effectiveness of the absorbing material used in an anechoic chamber. This alone is not enough to determine a figure of merit for an anechoic chamber or to compare the figure of merit for one anechoic chamber to that of another. While the information gained

R. R. DeLyser; C. L. Holloway; R. T. Johnk; A. R. Ondrejka; M. Kanda

1996-01-01

41

Electromagnetic Anechoic Chambers used from Microwaves to Millimeter-Waves and Ultra Broadband Wave Absorbers  

Microsoft Academic Search

The electromagnetic anechoic chambers have been widely used for many purposes with the advance of communications from microwaves to millimeter-waves. In this paper, the electromagnetic anechoic chamber used from microwaves to millimeter-waves is explained, and the ultra broadband wave absorbers for these electromagnetic anechoic chambers are stated. The some recent results of measurement are shown to ascertain the performance of

Hiroshi Kurihara; Takashi Tanaka; Toshifumi Saito; Motonari Yanagawa

2004-01-01

42

Comparison of electromagnetic absorber used in anechoic and semi-anechoic chambers for emissions and immunity testing of digital devices  

Microsoft Academic Search

The absorber used in anechoic and semi-anechoic chambers employed for emissions and immunity testing of digital devices is examined. Using reflectivities obtained by the method of homogenization, the advantages and disadvantages of urethane pyramids, twisted-pyramids, wedges, as well as ferrite tiles, ferrite grids, and “hybrid” combinations of urethanes and ferrites, are determined. General reflectivity guidelines are also presented for comparing

Christopher L. Holloway; Ronald R. DeLyser; Robert F. German; Paul McKenna; Motohisa Kanda

1997-01-01

43

Evaluation of anechoic chamber characteristics using optically driven equipment under test  

Microsoft Academic Search

The characteristics of an anechoic chamber lined with a foamed ferrite that can be composed as fully and semi-anechoic is evaluated using optically driven equipment under test (EUT). Measurement of the radiated emission from the developed EUT are performed for both fully and semi-anechoic dispositions of the chamber. The difference between measured values of normalized site attenuation (NSA) for the

J. C. Aquino; T. Kawashima; M. Tokuda

1999-01-01

44

Analysis of Anechoic Chamber Testing of the Hurricane Imaging Radiometer  

NASA Technical Reports Server (NTRS)

The Hurricane Imaging Radiometer System (HIRAD) is a new airborne passive microwave remote sensor developed to observe hurricanes. HIRAD incorporates synthetic thinned array radiometry technology, which use Fourier synthesis to reconstruct images from an array of correlated antenna elements. The HIRAD system response to a point emitter has been measured in an anechoic chamber. With this data, a Fourier inversion image reconstruction algorithm has been developed. Performance analysis of the apparatus is presented, along with an overview of the image reconstruction algorithm

Fenigstein, David; Ruf, Chris; James, Mark; Simmons, David; Miller, Timothy; Buckley, Courtney

2010-01-01

45

Methods for Locating Stray-Signal Sources in Anechoic Chambers  

Microsoft Academic Search

Two complementary numerically efficient frequency-domain methods for locating stray-signal sources in anechoic chambers are investigated and applied in combination to actual measurement data. Both methods use single-frequency near-field data collected on a planar surface and process them to reconstruct field values (images) elsewhere. The first method, which is based on the fact that the probe output satisfies the Helmholtz equation,

Thorkild B. Hansen; Richard A. Marr; Justin S. Hsia; Kristopher T. Kim; Uve H. W. Lammers; Jimmie J. Perez; Timothy J. Tanigawa

2008-01-01

46

Reflectivity level of RF shielded anechoic chamber  

Microsoft Academic Search

The reflectivity level of an RF shielded rectangular chamber with a non-uniform absorber lining has been investigated using the geometrical optics approach. The excitation antennas considered are the Hertzian dipole, a halfwave dipole and a pyramidal horn. A simple model is employed for the reflectivity of the absorber lining for normal incidence

S. V. K. Shastry; S. K. Nagesh; D. Binu

1995-01-01

47

Shielding effectiveness measurements of a shielded window: comparative results obtained using mode-stirred and anechoic chambers  

Microsoft Academic Search

This paper discusses results of shielding effectiveness (SE) testing of a shielded window in a mode-stirred Chamber (MSC) and in an anechoic chamber. It shows that the agreement between the MSC and anechoic chamber SE data is good when a large number of aspect angles are tested in the anechoic chamber and when the same equation (with modifications appropriate for

D. Mark Johnson; M. O. Hatfield

1995-01-01

48

Efficient detection of resonances in anechoic chambers using the matrix pencil method  

Microsoft Academic Search

In a previous paper we have presented a method for evaluating the performance of anechoic chambers by analyzing the S-parameters of a system comprising two antennas facing each other in an anechoic chamber using the matrix pencil method. In this work, we present an improvement of this resonance detection technique using only the transmission parameter S21. The propagating components of

Benoît Fourestié; Zwi Altman; Motohisa Kanda

2000-01-01

49

Reflectivity measurements in anechoic chambers in the microwave to millimeter range  

Microsoft Academic Search

A voltage standing-wave ratio (VSWR) measurement method and ensuing reflectivity characteristics are presented for anechoic chambers in the range 1-76.5 GHz. The free space VSWR measurements are performed using a composite antenna technique. By making use of two different anechoic chambers, the dependency of the reflectivity characteristics upon direction in the horizontal plane and absorber's height is analyzed.

Hithoshi Togawa; Kennichi Hatakeyama; Kenji Yamauchi

2005-01-01

50

Analysis and design of 4-wire antenna for anechoic chamber excitation  

Microsoft Academic Search

In order to illuminate a uniform field at a target area in an anechoic chamber over a wide frequency range, a 4-wire antenna is proposed. This antenna consists of two V-antennas spreading away from each other from the feed point. Antenna parameters are determined for a given dimension of the anechoic chamber. Numerical analysis shows that the 4-wire antenna has

Valdis V. Liepa; Changyul Cheon

1989-01-01

51

Comparison of Ergodic Capacities From Wideband MIMO Antenna Measurements in Reverberation Chamber and Anechoic Chamber  

Microsoft Academic Search

It has previously been shown that ergodic mul- tiple-input-multiple-output (MIMO) capacity of a multiport antenna system can be conveniently determined from channel measurements in a reverberation chamber. In this letter, we compare such MIMO capacity results to results based on mea- surements in an anechoic chamber of the embedded far-field functions and efficiencies at all antenna ports. The comparison is

Xiaoming Chen; Per-Simon Kildal; Jan Carlsson; Jian Yang

2011-01-01

52

Ultrasonic anechoic chamber qualification: accounting for atmospheric absorption and transducer directivity.  

PubMed

Qualifying an anechoic chamber for frequencies that extend into the ultrasonic range is necessary for research work involving airborne ultrasonic sound. The ANSI S12.55/ISO 3745 standard which covers anechoic chamber qualification does not extend into the ultrasonic frequency range, nor have issues pertinent to this frequency range been fully discussed in the literature. An increasing number of technologies employ ultrasound; hence the need for an ultrasonic anechoic chamber. This paper will specifically discuss the need to account for atmospheric absorption and issues pertaining to source transducer directivity by presenting some results for qualification of a chamber at Brigham Young University. PMID:21877773

Jenny, Trevor; Anderson, Brian E

2011-08-01

53

Numerical methodologies for optimizing and predicting the low frequency behavior of anechoic chambers.  

PubMed

This paper presents a description of the use of simplified numerical methodologies for the optimization of the low cut-off frequency of anechoic and hemi-anechoic chambers. The anechoic chamber is modeled as a cavity with proper surface impedance boundary conditions. First, the shape of the wedges is optimized by means of a minimization-based procedure of a finite element model of such elements in a "virtual" impedance tube for a plane wave field. An equivalent surface impedance of the wedges is determined from those data. An analytical procedure is then used to determine the complex reflection coefficient for spherical waves at oblique incidence. Finally, a complex image source approach is used to predict the sound field within the chamber. The methodology is applied to two anechoic chambers and the results are compared in terms of sound decay along fixed directions and surface pressure distributions. PMID:23862806

Bonfiglio, Paolo; Pompoli, Francesco

2013-07-01

54

The New Anechoic Shielded Chambers Designed for Space and Commercial Applications at LIT  

NASA Technical Reports Server (NTRS)

The main objective of this paper is to present the capabilities of the new anechoic shielded rooms designed for space and commercial applications as part of the Integration and Testing Laboratory (LIT, Laboratorio de Integracao e Testes) in Brazil. A new anechoic shielded room named CBA2 has been in full operation since March 2007 and a remodeled chamber CBA1 is planned to be ready by the end of 2008, replacing an old facility which was in operation for the last 18 years. The Brazilian Space Program started with very small and simple satellites and the old CBA1 chamber was conceived in 1987 to accomplish the EMI/EMC tests not requiring significant volumes. Since the very beginning this facility was also used by the private sector for other applications mainly due to the absorption of digital electronics in all kind of products. The intense use of this facility during the last years, operating three shifts a day, caused a normal degradation and imposed several limitations. Therefore, a new totally remodeled chamber was designed considering the state of the art in terms of absorbers and associated instrumentation. On the other hand the facility CBA2 was conceived, designed and implemented to test large satellites taking into account the advance of the technology in terms of RF frequencies, power level, testing methodologies and several other factors. A very interesting and unique aspect of this project was the partnership between the private sector and governmental institution. As a result, the total investment was shared between several companies and consequently a time-sharing use of the facility as well.

da Silva, Benjamim; Galvao, M. C.; Pereira, Clovis Solano

2008-01-01

55

Analysis of semi-anechoic chamber using ray-tracing technique  

Microsoft Academic Search

A semi-anechoic chamber is known to be useful for EMC measurements in a frequency range from 30 MHz to 1000 MHz. The analysis using a ray-tracing technique is investigated to evaluate a normalized site attenuation in the semi-anechoic chamber which is used for EMC measurements in a 3 m or 10 m method. The validity of the analysis is verified

Hiroki Anzai; T. Kishimoto; T. Yamazaki; Y. Naito; T. Mizumoto

1996-01-01

56

Anechoic chamber qualification: Traverse method, inverse square law analysis method, and nature of test signal  

Microsoft Academic Search

Qualification of anechoic chambers is intended to demonstrate that the chamber supports the intended free-field environment within some permissible tolerance bounds. Key qualification issues include the method used to obtain traverse data, the analysis method for the data, and the use of pure tone or broadband noise as the chamber excitation signal. This paper evaluates the relative merits of continuous

Kenneth A. Cunefare; Van B. Biesel; John Tran; Ryan Rye; Aaron Graf; Mark Holdhusen; Anne-Marie Albanese

2003-01-01

57

Comparison between radiation efficiencies of phone antennas and radiated power of mobile phones measured in anechoic chambers and reverberation chamber  

Microsoft Academic Search

Chalmers University and Bluetest AB have developed a reverberation chamber that can be used to measure radiation efficiency of phone antennas and the radiated power of mobile phones. This paper describes the verification of the reverberation chamber measurements by comparison with two anechoic chambers. The total radiated power of each of ten different mobile phone models was measured. In addition,

Nikolay Serafimov; Per-Simon Kildal; T. Bolin

2002-01-01

58

Inlet noise on 0.5-meter-diameter NASA QF-1 fan as measured in an unmodified compressor aerodynamic test facility and in an anechoic chamber  

NASA Technical Reports Server (NTRS)

Narrowband analysis revealed grossly similar sound pressure level spectra in each facility. Blade passing frequency (BPF) noise and multiple pure tone (MPT) noise were superimposed on a broadband (BB) base noise. From one-third octave bandwidth sound power analyses the BPF noise (harmonics combined), and the MPT noise (harmonics combined, excepting BPF's) agreed between facilities within 1.5 db or less over the range of speeds and flows tested. Detailed noise and aerodynamic performance is also presented.

Gelder, T. F.; Soltis, R. F.

1975-01-01

59

Comparison of anechoic and reverberation chamber coupling data as a function of directivity pattern. II  

Microsoft Academic Search

This paper extends previous work on comparing data from anechoic and reverberation chamber tests. Since the test electromagnetic environment in the two techniques are different, one-to-one comparisons of equipment responses are difficult. Responses in both anechoic and reverberation tests depend on equipment directivity but in different ways. The expected results also have different dependencies on variations in test conditions (e.g.,

Gustav J. Freyer; Mats G. Backstrom

2001-01-01

60

Validating anechoic chambers above 1 GHz using a reciprocal site VSWR technique  

Microsoft Academic Search

In this paper, three validation methods for anechoic chambers above 1 GHz are presented. They are related to the Site VSWR concept developed by CISPR\\/A. The reciprocal site VSWR method as well as the site VSWR method are proper methods to validate EMC chambers. The use of omnidirectional field probes and omnidirectional antenna does not have a significant impact on

Alexander Kriz

2005-01-01

61

OPTIMIZATION AN ANECHOIC CHAMBER WITH RAY-TRACING AND GENETIC ALGORITHMS  

Microsoft Academic Search

Anechoic chambers are used for both emission and immunity testing but the ferrite tiles used to line the inside of the chamber are extremely expensive.This paper describes a method of reducing the number of tiles, whilst ensuring a reliable test environment. In this paper, the ray-tracing method for waves propagation is used for evaluation of the reflectivity level of an

Sayed Mohammad Javad Razavi; Mohammad Khalaj-Amirhosseini

2008-01-01

62

Anechoic Chamber test of the Electromagnetic Measurement System ground test unit  

SciTech Connect

The Electromagnetic Measurement System (EMMS) will acquire data on electromagnetic (EM) environments at key weapon locations on various aircraft certified for nuclear weapons. The high-frequency ground unit of the EMMS consists of an instrumented B61 bomb case that will measure (with current probes) the localized current density resulting from an applied EM field. For this portion of the EMMS, the first system test was performed in the Anechoic Chamber Facility at Sandia National Laboratories, Albuquerque, New Mexico. The EMMS pod was subjected to EM radiation at microwave frequencies of 1, 3, and 10 GHz. At each frequency, the EMMS pod was rotated at many positions relative to the microwave source so that the individual current probes were exposed to a direct line-of-sight illumination. The variations between the measured and calculated electric fields for the current probes with direct illumination by the EM source are within a few db. The results obtained from the anechoic test were better than expected and verify that the high frequency ground portion of the EMMS will accurately measure the EM environments for which it was designed.

Stevenson, L.E.; Scott, L.D.; Oakes, E.T.

1987-04-10

63

Numerical and experimental analysis of the field to enclosure coupling in reverberation chamber and comparison with anechoic chamber  

Microsoft Academic Search

This paper presents a study of coupling between an external field and a metallic enclosure with a long aperture in the frequency range which includes several box resonances. A reverberation chamber (RC) and an anechoic chamber (AC) are considered as a field generation structure. In both cases, a customized FDTD code is used to calculate the current induced by the

G. Gradoni; F. Moglie; A. P. Pastore; V. M. Primiani

2006-01-01

64

OTA measurements of wireless stations in reverberation chamber versus anechoic chamber: from accuracy models to testing of MIMO systems  

Microsoft Academic Search

The paper will describe the fundamental characteristics of different wave propagation environments (such as Rayleigh fading, Rice fading, and polarization balance; coherence bandwidth and time delay spread; and fading speed, coherence time and Doppler spread), and relate these characteristics to the Line-Of-Sight (LOS) emulated by good anechoic chambers, and the rich isotropic multipath environment emulated by good reverberation chambers. The

Per-Simon Kildal

2010-01-01

65

Boundary element evaluation on the performance of sound absorbing wedges for anechoic chambers  

Microsoft Academic Search

In the present study, the acoustic performance analysis for wedges used in an anechoic chamber by the boundary element method is conducted. In a wedge formed by porous material, mechanisms of dissipated processes due to viscosity and heat conduction are very complicated and are not easy to handle. For simplicity, the laws of Delany and Bazley are used to replace

Chao-Nan Wang; Ming-Kun Tang

1996-01-01

66

Experimental study on direction dependency of reflection coefficients of microwave electromagnetic anechoic chamber  

Microsoft Academic Search

For measurements of reflection coefficients in an anechoic chamber by the free-space voltage standing wave ratio (VSWR) method, the composite antenna technique, using a combination of two antennas, is proposed. Reliable data on reflection coefficients can be obtained by this technique, with respect to reflected waves from arbitrary directions. Using the measurement results, the direction dependency of reflection coefficients is

K. Hatakeyama; H. Togawa; T. Kawamura; Y. Sato

1992-01-01

67

30-1000 MHz field strength standard developed in anechoic chamber  

Microsoft Academic Search

An accurate electric field strength for the frequency range of 30 MHz to 1000 MHz has been developed in a full anechoic chamber with 1-? uncertainty less than ±1.9%. Reflection parameters of walls at frequencies below 200 MHz are evaluated experimentally, and the errors due to these waves are compensated in the standard and calibrations of the antennas

Toshimi Matsui

1992-01-01

68

New imitated equipment with optical powering system for evaluating anechoic chamber characteristics  

Microsoft Academic Search

In order to evaluate the characteristics of an anechoic chamber, a new optically driven imitated equipment with optical powering system is developed. The optical powering system consists of high power laser diode, optical fiber and photovoltaic cells. This serves as the electric power source which does not use any metal cables and operates for a much longer period of time

Takahiro NANGO; T. Kawashina; Junichi OHWAKI; Masamitsu TOKUDA

2001-01-01

69

The effects of RF absorbers on measurements of small antennas in small anechoic chambers  

Microsoft Academic Search

In this work the influence of resistive absorbers in the vicinity of small antennas was investigated, in order to define a lower limit for the size of a small anechoic chamber for antenna calibration and radiation pattern measurements, with respect to the distance between the antenna under test (AUT) and the RF absorbers lining the walls. Furthermore, the influence of

C. Icheln; J. Ollikainen; P. Vainikainen

1999-01-01

70

Numerical modeling of a stripline antenna in a large semi-anechoic chamber  

Microsoft Academic Search

Stripline antennas are used for automotive immunity testing in semi-anechoic chambers at low frequencies (<30 MHz). In order to investigate the behavior of such devices, a numerical model of the radiating elements of such a system has been developed using a 3D field modeling technique (TLM). The field distribution beneath this structure has also been measured for comparison with the

Alastair R. Ruddle; David D. Ward; Simon C. Pomeroy

2001-01-01

71

Reducing the computational domain for FDTD scattering simulation using the sawtooth anechoic chamber ABC  

Microsoft Academic Search

A novel absorbing boundary condition (ABC), to be used with finite difference electromagnetic scattering simulation is described. This new ABC is based on modeling lossy anechoic chamber foam pyramids as a lattice terminating layer. The advantage of this absorbing boundary is that it prevents reflections from much wider incident angles than most currently used techniques, yet is conceptually straightforward, simple

Carey M. Rappaport; Tolga Gurel

1995-01-01

72

Experimental evaluation of a SAGE algorithm for ultra wideband channel sounding in an anechoic chamber  

Microsoft Academic Search

The paper presents the results of experiments in an anechoic chamber that assessed the reliability of a UWB channel sounding system based on a deterministic approach with a SAGE algorithm. The system could resolve and detect waves separated by 10° in the angle domain, which was near the resolution limit. In the delay domain, waves separated by 0.67 ns could

K. Haneda; J. I. Takada; T. Kobayashi

2004-01-01

73

Microwave field-to-wire coupling measurements in anechoic and reverberation chambers  

Microsoft Academic Search

Knowledge of the differences in radiated susceptibility (RS) testing in anechoic (AC) and reverberation chambers (RC) is essential for analysis of the susceptibility of electronic systems to microwave radiation. We have studied microwave field-to-wire coupling for some basic wire geometries above a ground plane in ACs and RC. Results for receiving parameters such as the antenna receiving cross section ?

Stefan Silfverskiöld; Mats Bäckström; Jörgen Lorén

2002-01-01

74

Effects of RF absorbers on measurements of small antennas in small anechoic chambers  

Microsoft Academic Search

In this work, the influence of resistive absorbers in the vicinity of small antennas was investigated, in order to define a lower limit for the size of a small anechoic chamber for antenna calibration and radiation pattern measurements, with respect to the distance between the antenna under test (AUT) and the RF absorbers lining the walls. Furthermore, the influence of

C. Icheln; J. Ollikainen; P. Vainikainen

2001-01-01

75

Prediction of anechoic chamber radiated emissions measurements through use of empirically-derived transfer functions and laboratory common-mode current measurements  

Microsoft Academic Search

In this study common-mode current measurements made in a laboratory (without an anechoic chamber) were correlated with radiated emissions measurements (made in an anechoic chamber) over a broad frequency range. The goal was to evaluate the use of current measurements as an alternative to avoid repeated testing of an electronic device in an anechoic chamber while improvements are made to

William T. Smith; R. Keith Frazier

1998-01-01

76

Reduction of fan noise in an anechoic chamber by reducing chamber wall induced inlet flow disturbances  

NASA Technical Reports Server (NTRS)

The difference between the flight and ground static noise of turbofan engines has been identified as a significant problem in engine noise testing. The additional noise for static testing has been attributed to inlet flow disturbances or turbulence interacting with the fan rotor. In an attempt to determine a possible source of inflow disturbances entering fans tested in the Lewis Research Center anechoic chamber the inflow field was studied using potential flow analysis. These potential flow calculations indicated that there was substantial flow over the wall directly behind the fan inlet that could produce significant inflow disturbances. Fan noise tests were run with various extensions added to the fan inlet to move the inlet away from this backwall and thereby reduce the inlet flow disturbances. Significant noise reductions were observed with increased inlet length. Over 5 dB reduction of the blade passage tone sound power level was observed between the shortest and longest inlets at 90% fan speed and the first overtone was reduced 9 dB. High frequency broadband noise was also reduced.

Dittmar, J. H.; Mackinnon, M. J.; Woodward, R. P.

1978-01-01

77

Reduction of fan noise in an anechoic chamber by reducing chamber wall induced inlet flow disturbances  

NASA Technical Reports Server (NTRS)

The difference between the flight and ground static noise of turbofan engines presents a significant problem in engine noise testing. The additional noise for static testing has been attributed to inlet flow disturbances or turbulence interacting with the fan rotor. In an attempt to determine a possible source of inflow disturbances entering fans tested in the Lewis Research Center anechoic chamber, the inflow field was studied using potential flow analysis. These potential flow calculations indicated that there was substantial flow over the wall directly behind the fan inlet that could produce significant inflow disturbances. Fan noise tests were run with various extensions added to the fan inlet to move the inlet away from this backwall and thereby reduce the inlet flow disturbances. Significant noise reductions were observed with increased inlet length. Over 5 db reduction of the blade passage tone sound power level was observed between the shortest and longest inlets at 90% fan speed and the first overtone was reduced 9 db. High frequency broadband noise was also reduced.

Dittmar, J. H.; Mackinnon, M. J.; Woodward, R. P.

1978-01-01

78

Analysis of Site Attenuation for an Anechoic Chamber using FI Method  

NASA Astrophysics Data System (ADS)

In this paper, to calculate site attenuation of anechoic chamber, we applied the FI method that was used Maxwell's relations with the integration form. First, in order to examine the influence of the cell size on the site attenuation calculation, we compared with the difference between the calculations values of a 30MHz tuned dipole antenna and a shortened dipole antenna using 40MHz tuned dipole antenna at the frequency of 30MHz. As a result, it was necessary for the 30MHz tuned dipole antenna to be 50 divisions to the wavelength of 30MHz, but, for the shortened dipole antenna to be 300 divisions to the wavelength. In order to examine this cause, we calculated the electric field in the antenna surroundings by the moment method (NEC2), and found that the change of the electric field distribution around the shortened dipole antenna was steeper than that around the tuned dipole antenna. Therefore, it is thought that the difference of the electric field distribution with this antenna was the cause mentioned above. The best size of the cell was presumed from the examination mentioned above, and we calculated the site attenuations of an open area test site and an anechoic chamber by the FI method. As for the open area test site, the calculation value by the FI method agreed with that by the moment method within 0.4dB. As for the anechoic chamber, the calculation value by the FI method was corresponding to the actual measurement value within 0.5dB by setting the cell size of 2cm. Therefore, it was confirmed that the FI method is effective for the calculation of site attenuation on the anechoic chamber.

Ishizuka, Kazuo; Terada, Kousei; Tokuda, Masamitsu

79

Reflectivity level of double-bounce rays in rectangle anechoic chamber  

NASA Astrophysics Data System (ADS)

The reflectivity level of double-bounce rays of a mini rectangular anechoic chamber with a uniform absorber lining has been investigated by using the geometrical optics approach. The influence of the reflectivity level of the double-bounce rays has been analyzed in Hertzian dipole excitation antennas as compared with that of single-reflection specular rays from the side walls including the ceiling and floor. The result shows that the effect of the double-bounce rays on the total reflectivity level is relatively unimportant and can be ignored at excitation frequency range from 500MHz to 8GHz for the chamber.

Liu, Rubing; Liu, Haitao; Chen, Zhigang; Lin, Qi

2013-03-01

80

An open-boundary quad-ridged guide horn antenna for use as a source in antenna pattern measurement anechoic chambers  

Microsoft Academic Search

The present paper introduces a new antenna design to be used in anechoic chambers. When measuring three-dimensional patterns, the receiving antenna in the anechoic chamber must be able to sense the two orthogonal components of the field that exist in the far field. This can be accomplished by mechanically rotating the source horn in the chamber. A better and faster

Vicente Rodriguez

2006-01-01

81

Radiated immunity testing of a device with an external wire: repeatability of reverberation chamber results and correlation with anechoic chamber results  

Microsoft Academic Search

We present the experimental radiated immunity results of an electronic device with an external wire obtained in reverberation and anechoic chambers. Repeatability and reproducibility of reverberation chamber measurements are investigated by repeating the test in three reverberation chambers with different characteristics. We show how the current state of the art allows a statistical control of RC measurement repeatability within an

L. Musso; F. Canavero; B. Demoulin; V. Berat

2003-01-01

82

Different Results of Radiated Emissions in Fully and Semi-Anechoic Chamber due to Influence of EUTís Vertical Cables Termination  

Microsoft Academic Search

Influence of EUT's vertical cables termination in fully and semi-anechoic chamber has been investigated. Numerical calculation and experimental results are presented for end-driven wire model (EDW) of equipment under test (EUT) with one cable. The investigation shows comparable results in different type of chambers for EUTs with cables terminated with absorbing clamp

G. Kova; R. Lapuh

2005-01-01

83

Acoustic noise caused by a.c. corona on conductors: Results of an experimental investigation in the anechoic chamber  

Microsoft Academic Search

The paper describes an experimental research performed in the anechoic chamber with the aim of investigating the qualitative and quantitative characteristics of the acoustic noise caused by a.c.corona on conductors. Conductors of different type and size, smooth and stranded, with and without surface treatment, were tested dry and wet within a large range of voltage gradients. On the basis of

M. Sforzini; R. Cortina; G. Sacerdote; R. Piazza

1975-01-01

84

Filtering environmental reflections in far-field antenna measurement in semi-anechoic chambers by an adaptive pattern strategy  

Microsoft Academic Search

A method to perform antenna far-field measurements in semi-anechoic chamber is presented. The method requires the measurement of the amplitude and phase of the pattern of the antenna under test in different spatial positions. The data are elaborated to estimate the direction of arrival of the reflected signals and to synthesize a receiving pattern with s in these directions. Experimental

M. D. Migliore

2004-01-01

85

Applications of time-gating method to improve the measurement accuracy of antenna radiation inside an anechoic chamber  

Microsoft Academic Search

In order to increase the quiet zone space, reduce the multi-path interferences and increase the measurement accuracy in an existing anechoic chamber, a time gating method (TGM) is incorporated into the measurement system. The TGM transforms the frequency domain (FD) response into time domain (TD) using a Fourier transform and filters out the late time pulses, which are caused by

Yu-Ting Hsiao; Yo-Yi Lin; Yu-Cheng Lu; Hsi-Tseng Chou

2003-01-01

86

Some acoustical properties of the anechoic chamber at the Centro de Instrumentos, Universidad Nacional Autónoma de México  

Microsoft Academic Search

Some of the basic acoustical properties of an anechoic chamber recently brought to operation are described. The background noise levels and sound insulation of doors were measured. The free field conditions in different directions and frequencies were determined using nondirectional sources.

Ricardo R Boullosa; A Pérez López

1999-01-01

87

A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber  

SciTech Connect

Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system.

Chiang, W. Y.; Wu, M. H.; Wu, K. L.; Lin, M. H.; Teng, H. H.; Barnett, L. R.; Chu, K. R., E-mail: krchu@yahoo.com.tw [Department of Physics, National Taiwan University, Taipei, Taiwan (China); Tsai, Y. F.; Ko, C. C.; Yang, E. C. [Department of Entomology, National Taiwan University, Taipei, Taiwan (China); Jiang, J. A. [Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, Taipei, Taiwan (China)

2014-08-15

88

ATS 6 EMI field measurements techniques and results. [anechoic chamber scale model testing  

NASA Technical Reports Server (NTRS)

At the present time 'Applications Technology Satellite (ATS)-6' is the world's largest communication satellite. It handles telecommunications in the frequency range of 40 - 30,000 MHz. Power levels on board the spacecraft range from -110 dBm to 52.5 dBw. Consequently considerable care was required in the design and test of this spacecraft, in order to provide assurances that the spacecraft would perform properly in its own RF environments. The testing was performed first by placing the earth viewing module (EVM) in a specially constructed 'small' anechoic chamber with an overhead parabolic reflector section, of 8' in diameter, instead of the 30' reflector of the full scale design. The near field analysis of this paper proves that this test configuration leads to a desirable overtest for the spacecraft. The test requirements, procedure and results are also explained.

Afifi, M. S.; Keiser, B. E.

1974-01-01

89

A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber.  

PubMed

Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system. PMID:25173291

Chiang, W Y; Wu, M H; Wu, K L; Lin, M H; Teng, H H; Tsai, Y F; Ko, C C; Yang, E C; Jiang, J A; Barnett, L R; Chu, K R

2014-08-01

90

A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber  

NASA Astrophysics Data System (ADS)

Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system.

Chiang, W. Y.; Wu, M. H.; Wu, K. L.; Lin, M. H.; Teng, H. H.; Tsai, Y. F.; Ko, C. C.; Yang, E. C.; Jiang, J. A.; Barnett, L. R.; Chu, K. R.

2014-08-01

91

Investigation on High Performance of 10m Semi Anechoic Chamber by using Open-Top Hollow Pyramidal Hybrid EM Wave Absorber  

Microsoft Academic Search

The emission radiated from electric and electronic equipments is evaluated through OATS. Recently, it is not fully prepared the environment for OATS because of a variety of communication radiation sources (e.g., digital television broadcast and cellular phone station). Therefore, the EM anechoic chambers are becoming more and more important as EMI test site. On the other hand, the EM anechoic

Hiroshi Kurihara; Toshifumi Saito; Yoshikazu Suzuki; Atsuhiro Nishikata; Osamu Hashimoto

2005-01-01

92

Effect of inflow control on inlet noise of a cut-on fan. [in an anechoic chamber  

NASA Technical Reports Server (NTRS)

The control of turbulence and other inflow disturbances in anechoic chambers for static turbofan noise studies was studied. A cut-on, high tip speed fan stage was acoustically tested with three configurations of an inflow control device in an anechoic chamber. Although this was a cut-on design, rotor inflow interaction appeared to be a much stronger source of blade passing tone radiated from the inlet than rotor stator interaction for the 1.6 mean rotor chord separation. Aft external suction applied to the area where the inflow control device joined the inlet produced a further reduction in blade passing tone, suggesting that disturbances in the forward flow on the outside of the inlet were superimposed on the inlet boundary layer and were a significant source of tone noise.

Woodward, R. P.; Glaser, F. W.

1980-01-01

93

Calibration of the Ames Anechoic Facility. Phase 1: Short range plan  

NASA Technical Reports Server (NTRS)

A calibration was made of the acoustic and aerodynamic characteristics of a small, open-jet wind tunnel in an anechoic room. The jet nozzle was 102 mm diameter and was operated subsonically. The anechoic-room dimensions were 7.6 m by 5.5 m by 3.4 m high (wedge tip to wedge tip). Noise contours in the chamber were determined by various jet speeds and exhaust collector positions. The optimum nozzle/collector separation from an acoustic standpoint was 2.1 m. Jet velocity profiles and turbulence levels were measured using pressure probes and hot wires. The jet was found to be symmetric, with no unusual characteristics. The turbulence measurements were hampered by oil mist contamination of the airflow.

Hickey, D.; Soderman, P. T.; Karamcheti, K.; Koutsoyannis, S. P.; Hopkins, R.; Mclachlan, B.

1980-01-01

94

Investigation on High Performance of 10m Semi Anechoic Chamber by using Open-Top Hollow Pyramidal Hybrid EM Wave Absorber  

NASA Astrophysics Data System (ADS)

The emission radiated from electric and electronic equipments is evaluated through OATS. Recently, it is not fully prepared the environment for OATS because of a variety of communication radiation sources (e.g., digital television broadcast and cellular phone station). Therefore, the EM anechoic chambers are becoming more and more important as EMI test site. On the other hand, the EM anechoic chambers are needed high performance in order to cut down EMI countermeasure cost and calculate the antenna factor. The objective of this paper is mainly to present the EM wave absorber design in order to obtain within ±2dB against the theoretical site attenuation values in the 10m semi anechoic chamber at 30MHz to 300MHz. We get the necessary reflectivity of EM wave absorber by the basic site attenuation equation. We design the open-top hollow pyramidal new hybrid EM wave absorber consisted of 180cm long dielectric loss foam and ferrite tiles. Then, we design the 10m semi anechoic chamber by using the ray-tracing simulation and construct it in the size of L24m×W15.2m×H11.2m. More over, we measure the site attenuation of the constructed 10m semi anechoic chamber by using the broadband calculable dipole antennas. As the result, we confirm the validity of the designed open-top hollow pyramidal new hybrid EM wave absorber.

Kurihara, Hiroshi; Saito, Toshifumi; Suzuki, Yoshikazu; Nishikata, Atsuhiro; Hashimoto, Osamu

95

Antenna height scan for minimizing EUT emission measurement uncertainty in fully anechoic chambers above 1 GHz  

Microsoft Academic Search

Our aim in this research work is to propose a methodology on receiving antenna height scan in the fully anechoic room (FAR) to minimize uncertainty in obtaining maximum emission of equipments under test (EUT) that have multilobe radiation patterns at higher frequencies. An EUT with complex slots is measured. The radiation emission for five antenna heights from 1 m to

Tian Hong Loh; M. Alexander

2006-01-01

96

LLNL heart valve condition classification project anechoic testing results at the TRANSDEC evaluation facility  

SciTech Connect

This report first briefly outlines the procedures and support/activation fixture developed at LLNL to perform the heart valve tests in an anechoic-like tank at the US Navy Transducer Evaluation Facility (TransDec) located in San Diego, CA. Next they discuss the basic experiments performed and the corresponding experimental plan employed to gather meaningful data systematically. The signal processing required to extract the desired information is briefly developed along with some of the data. Finally, they show the results of the individual runs for each valve, point out any of the meaningful features and summaries.

Candy, J V

1999-10-31

97

Accurate and continuous non-contact vital signs monitoring using phased array antennas in a clutter-free anechoic chamber.  

PubMed

Continuous and accurate monitoring of human vital signs is an important part of the healthcare industry, as it is the basic means by which the clinicians can determine the instantaneous status of their patients. Doppler-based noncontact vital signs (NCVS) sensor systems can monitor the heart and respiration rates without touching the patient, but it has been observed that that the accuracy of these NCVS sensors can be diminished by reflections from background clutters in the measurement environment, and that high directivity antennas can increase the sensing accuracy. Therefore, this work explores a NCVS sensor with continuous data taken inside an anechoic chamber where the background cluttering is negligible. In addition, a high directivity custom-made beam-steerable phased array antenna system is used to improve the performance and functionality of the 2.4GHz NCVS sensor we have built. We believe this work is the 1st systematic study using Doppler-based phased array systems for NCVS sensing performed in a clutter-free anechoic chamber. PMID:24110324

Boothby, A; Das, V; Lopez, J; Tsay, J; Nguyen, T; Banister, R E; Lie, D Y C

2013-01-01

98

Effectiveness of an inlet flow turbulence control device to simulate flight fan noise in an anechoic chamber  

NASA Technical Reports Server (NTRS)

A hemispherical inlet flow control device was tested on a 50.8 cm. (20-inch) diameter fan stage in the NASA-Lewis Anechoic Chamber. The control device used honeycomb and wire mesh to reduce turbulence intensities entering the fan. Far field acoustic power level results showed about a 5 dB reduction in blade passing tone and about 10 dB reduction in multiple pure tone sound power at 90% design fan speed with the inlet device in place. Hot film cross probes were inserted in the inlet to obtain data for two components of the turbulence at 65 and 90% design fan speed. Without the flow control device the axial intensities were below 1.0%, while the circumferential intensities were almost twice this value. The inflow control device significantly reduced the circumferential turbulence intensities and also reduced the axial length scale.

Woodward, R. P.; Wazyniak, J. A.; Shaw, L. M.; Mackinnon, M. J.

1977-01-01

99

Effectiveness of an inlet flow turbulence control device to simulate flight noise fan in an anechoic chamber  

NASA Technical Reports Server (NTRS)

A hemispherical inlet flow control device was tested on a 50.8 cm. (20-inch) diameter fan stage in the NASA-Lewis anechoic chamber. The control device used honeycomb and wire mesh to reduce turbulence intensities entering the fan. Far field acoustic power level results show about a 5 db reduction in blade passing tone and about 10 dB reduction in multiple pure tone sound power at 90% design fan speed with the inlet device in place. Hot film cross probes were inserted in the inlet to obtain data for two components of the turbulence at 65 and 90% design fan speed. Without the flow control device, the axial intensities were below 1.0%, while the circumferential intensities were almost twice this value. The inflow control device significantly reduced the circumferential turbulence intensities and also reduced the axial length scale.

Woodward, R. P.; Wazyniak, J. A.; Shaw, L. M.; Mackinnon, M. J.

1977-01-01

100

Improved fire resistant radio frequency anechoic materials  

NASA Technical Reports Server (NTRS)

Protective, flameproof foam covering improves the resistance to fire and surface contamination of low-cost radio frequency absorbing and shielding anechoic materials. This promotes safety of operating personnel and equipment being tested in an otherwise combustible anechoic chamber.

Robinson, D. A.

1969-01-01

101

National Ignition Facility Target Chamber  

Microsoft Academic Search

On June 11, 1999 the Department of Energy dedicated the single largest piece of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The ten (10) meter diameter aluminum target high vacuum chamber will serve as the working end of the largest laser in the world. The output of 192 laser beams will converge at

R W Wavrik; J R Cox; P J Fleming

2000-01-01

102

Realization of 3 m Semi Anechoic Chamber by Using Crossed-Wedge Shaped Hybrid EM Wave Absorber Consisting of Thin Corrugated Dielectric Lossy Sheet  

NASA Astrophysics Data System (ADS)

This letter proposes a new hybrid EM wave absorber with the crossed-wedge shape, which can be applied to 3m semi anechoic chambers. In this study, we designed a new hybrid EM wave absorber with the crossed-wedge shape, which consisted of the inorganic and organic thin corrugated dielectric lossy sheet containing organic conductive fibers. Then the 3m semi anechoic chamber is constructed in the size of 9.0m × 6.0m × 5.7m (L × W × H) using these absorbers, and also the normalized site attenuation (NSA) is measured according to ANSI C63.4 in the frequency range of 30MHz to 1GHz. As a result, the measured NSA is obtained within ±3dB of the theoretical one.

Saito, Toshifumi; Suzuki, Yoshikazu; Kurihara, Hiroshi

103

Directivity of equipment and its effect on testing in mode-stirred and anechoic chamber  

Microsoft Academic Search

If radiated susceptibility testing in a mode-stirred chamber (MSC) is used to test equipment that in its real operation may become irradiated by plane waves it is necessary to increase the test level, i.e. add a margin. In order to find out typical magnitudes of this margin coupling measurements to the interior of several objects have been carried out both

Leif Jansson; Mats Backstrom

1999-01-01

104

Supervised Self-Organizing Classification of Superresolution ISAR Images: An Anechoic Chamber Experiment  

Microsoft Academic Search

The problem of the automatic classification of superresolution ISAR images is addressed in the paper. We describe an ane- choic chamber experiment involving ten-scale-reduced aircraft models. The radar images of these targets are reconstructed using MUSIC-2D (multiple signal classification) method coupled with two additional processing steps: phase unwrapping and symme- try enhancement. A feature vector is then proposed including Fourier

Emanuel Radoi; Andr ´ e Quinquis; Felix Totir

2006-01-01

105

Prediction of the scattering of a double periodic array of anechoic chamber pyramids by a surface integral equation approach  

Microsoft Academic Search

The scattering and absorption of a double periodic array of anechoic room pyramids backed by a perfect conductor is analyzed with a surface integral equation (SIE) approach. The use of a suitable periodic Green's function as the kernel of the SIE reduces the formulation of the problem of a single pyramid. The validity, flexibility, and accuracy of the SIE approach

N. Marly; D. De Zutter; L. Martens; H. Pues

1993-01-01

106

Space Power Facility Reverberation Chamber Calibration Report  

NASA Technical Reports Server (NTRS)

This document describes the process and results of calibrating the Space Environmental Test EMI Test facility at NASA Plum Brook Space Power Facility according to the specifications of IEC61000-4-21 for susceptibility testing from 100 MHz to 40 GHz. The chamber passed the field uniformity test, in both the empty and loaded conditions, making it the world's largest Reverberation Chamber.

Lewis, Catherine C.; Dolesh, Robert J.; Garrett, Michael J.

2014-01-01

107

Airframe noise measurements on a small-scale model of a supersonic transport concept in an anechoic flow facility  

NASA Technical Reports Server (NTRS)

Airframe noise has been measured on a .015 scale model of an advanced supersonic transport concept (AST-100) in an anechoic flow facility. The model was equipped with leading- and trailing-edge flaps, nose and main landing gears, and engine nacelles. Each of these components was deployed, individually and collectively, to determine their contribution to the noise field. Results are presented which show that in the clean configuration the aircraft displays a symmetric dipole directivity, whereas in the more complex landing-approach configuration the directivity peaks in the forward quadrant. It was found that the landing-approach noise was due chiefly to the landing gear, the trailing edge flaps, and the aeroacoustic interaction between the two

Preisser, J. S.

1979-01-01

108

New acoustic test facility at Georgia Tech  

Microsoft Academic Search

Georgia Tech's Integrated Acoustics Laboratory (IAL) is a state of the art research facility dedicated to the study of acoustics and vibration. The centerpiece of the laboratory is a 24 ft x24 ft x20 ft full anechoic chamber, which has been in operation since 1998. The IAL is currently expanding to include a reverberation room and hemi-anechoic chamber, designed and

Van Biesel; Kenneth Cunefare

2002-01-01

109

Directive Wavefronts Inside a Time Reversal Electromagnetic Chamber  

E-print Network

is generally between rever- beration chambers (RCs) and anechoic chambers (ACs) [4], taking into considerationDirective Wavefronts Inside a Time Reversal Electromagnetic Chamber Houmam Moussa, Andrea Cozza chamber (TREC) is investigated in order to propose the TREC system as an alternative EMC test facility

Boyer, Edmond

110

X-43A Undergoing Controlled Radio Frequency Testing in the Benefield Anechoic Facility at Edwards Ai  

NASA Technical Reports Server (NTRS)

The X-43A Hypersonic Experimental (Hyper-X) Vehicle hangs suspended in the cavernous Benefield Aenechoic Facility at Edwards Air Force Base during radio frequency tests in January 2000. Hyper-X, the flight vehicle for which is designated as X-43A, is an experimental flight-research program seeking to demonstrate airframe-integrated, 'air-breathing' engine technologies that promise to increase payload capacity for future vehicles, including hypersonic aircraft (faster than Mach 5) and reusable space launchers. This multiyear program is currently underway at NASA Dryden Flight Research Center, Edwards, California. The Hyper-X schedule calls for its first flight later this year (2000). Hyper-X is a joint program, with Dryden sharing responsibility with NASA's Langley Research Center, Hampton, Virginia. Dryden's primary role is to fly three unpiloted X-43A research vehicles to validate engine technologies and hypersonic design tools as well as the hypersonic test facility at Langley. Langley manages the program and leads the technology development effort. The Hyper-X Program seeks to significantly expand the speed boundaries of air-breathing propulsion by being the first aircraft to demonstrate an airframe-integrated, scramjet-powered free flight. Scramjets (supersonic-combustion ramjets) are ramjet engines in which the airflow through the whole engine remains supersonic. Scramjet technology is challenging because only limited testing can be performed in ground facilities. Long duration, full-scale testing requires flight research. Scramjet engines are air-breathing, capturing their oxygen from the atmosphere. Current spacecraft, such as the Space Shuttle, are rocket powered, so they must carry both fuel and oxygen for propulsion. Scramjet technology-based vehicles need to carry only fuel. By eliminating the need to carry oxygen, future hypersonic vehicles will be able to carry heavier payloads. Another unique aspect of the X-43A vehicle is the airframe integration. The body of the vehicle itself forms critical elements of the engine. The forebody acts as part of the intake for airflow and the aft section serves as the nozzle. The X-43A vehicles were manufactured by Micro Craft, Inc., Tullahoma, Tennessee. Orbital Sciences Corporation, Chandler, Arizona, built the Pegasus rocket booster used to launch the X-43 vehicles. For the Dryden research flights, the Pegasus rocket booster and attached X-43 will be air launched by Dryden's B-52 'Mothership.' After release from the B-52, the booster will accelerate the X-43A vehicle to the established test conditions (Mach 7 to 10) at an altitude of approximately 100,000 feet where the X-43 will separate from the booster and fly under its own power and preprogrammed control.

2000-01-01

111

Click to insert the image of the facility or test-rig  

E-print Network

frequency limit 63 Hz The large size anechoic chamber absorbs sound in all directions. Thus, it is a fully parameters including sound power, sound directivity patterns, etc. Anechoic Room Sound power measurements testing facility. Thus, sound transmission loss measurements with a reverberant sound field on one side

Berlin,Technische Universität

112

Emulating an Anechoic Environment in a Wave-Diffusive Medium through an Extended  

E-print Network

, a task often achieved by means of anechoic chambers (ACs), which rely on the use of electromagnetic1 Emulating an Anechoic Environment in a Wave-Diffusive Medium through an Extended Time. The proposed alternative technique, named Time-Reversal Electromagnetic Chamber (TREC) is introduced

Boyer, Edmond

113

A new environmental chamber facility for chemical mechanism and VOC  

NASA Astrophysics Data System (ADS)

Because of chemical mechanism uncertainties, environmental chamber experiments are used for developing and evaluating chemical mechanisms for air quality models for predicting the effects of volatile organic compounds (VOCs) and NO_x on formation of O_3 and other secondary pollutants. However, the chamber data base used for mechanisms in current models represent NO_x conditions much higher than generally present in current atmospheres, lack measurements of many key species, have either uncontrolled lighting or unrepresentative light spectra, and include no systematic data on temperature effects. Because this can result in uncertainties of model predictions of effects of control strategies on air quality, a new environmental chamber facility is being developed in the U.S. at the University of California at Riverside to address these limitations. This indoor chamber employs a 300 KW filtered Argon arc light source irradiating dual ˜80 m^3 in a temperature controlled "clean room" designed to minimize introduction of background pollutants, and has instrumentation to measure a number of species not monitored in most previous experiments. Tests were conducted using smaller prototype reactors to determine the lower limits for background effects. The construction of the facility has just been completed and characterization experiments are underway. Results to date and plans for ongoing research will be discussed.

Carter, W. P. L.; Fitz, D. R.; Sauer, C.; Bumiller, K.; Bufalino, C.; Malkina, I.; Pisano, J.; Smith, M.

2003-04-01

114

Electromagnetic Radiation (EMR) coupling to complex systems : aperture coupling into canonical cavities in reverberant and anechoic environments and model validation.  

SciTech Connect

Mode-stirred chamber and anechoic chamber measurements were made on two sets of canonical test objects (cylindrical and rectangular) with varying numbers of thin slot apertures. The shielding effectiveness was compared to determine the level of correction needed to compensate the mode-stirred data to levels commensurate with anechoic data from the same test object.

Charley, Dawna R.; Higgins, Matthew B.

2007-12-01

115

Anechoic Chamber o Echoless Room, existing equipment  

E-print Network

students to run demonstration Hydraulics Lab o Existing Equipment o Hydraulic jumps, or model of Saskatoon Equipment o Demonstrates tensile failure mechanisms of different metals o Need Students to run demonstration on a free spinning plate with there arms stretched out, start them spinning slowly, then tell them to pul

Saskatchewan, University of

116

Static and wind tunnel near-field/far-field jet noise measurements from model scale single-flow base line and suppressor nozzles. Summary report. [conducted in the Boeing large anechoic test chamber and the NASA-Ames 40by 80-foot wind tunnel  

NASA Technical Reports Server (NTRS)

A test program was conducted in the Boeing large anechoic test chamber and the NASA-Ames 40- by 80-foot wind tunnel to study the near- and far-field jet noise characteristics of six baseline and suppressor nozzles. Static and wind-on noise source locations were determined. A technique for extrapolating near field jet noise measurements into the far field was established. It was determined if flight effects measured in the near field are the same as those in the far field. The flight effects on the jet noise levels of the baseline and suppressor nozzles were determined. Test models included a 15.24-cm round convergent nozzle, an annular nozzle with and without ejector, a 20-lobe nozzle with and without ejector, and a 57-tube nozzle with lined ejector. The static free-field test in the anechoic chamber covered nozzle pressure ratios from 1.44 to 2.25 and jet velocities from 412 to 594 m/s at a total temperature of 844 K. The wind tunnel flight effects test repeated these nozzle test conditions with ambient velocities of 0 to 92 m/s.

Jaeck, C. L.

1977-01-01

117

Trade study comparing specimen chamber servicing methods for the Space Station Centrifuge Facility  

NASA Technical Reports Server (NTRS)

The Specimen Chamber Service Unit, a component of the Space Station Centrifuge Facility, must provide a clean enclosure on a continuing basis for the facility's plant, rodent and primate specimens. The specimen chambers can become soiled and can require periodic servicing to maintain a clean environment for the specimens. Two methods of servicing the specimen chambers are discussed: washing the chambers with an on-board washer, or disposing of the soiled chambers and replacing them with clean ones. Many of these issues are addressed by developing several servicing options, using either cleaning or replacement as the method of providing clean specimen chambers, and then evaluating each option according to a set of established quantitative and qualitative criteria. Disposing and replacing the Specimen Chambers is preferable to washing them.

Calvisi, Michael L.; Sun, Sidney C.

1991-01-01

118

The Kevlar-walled anechoic wind tunnel  

NASA Astrophysics Data System (ADS)

The aerodynamic and acoustic performance of an anechoic wind tunnel test section with walls made from thin Kevlar cloth have been measured and analyzed. The Kevlar test section offers some advantages over a conventional free-jet arrangement. The cloth contains the bulk of the flow but permits the transmission of sound with little loss. The containment results in smaller far-field aerodynamic corrections meaning that larger models can be tested at higher Reynolds numbers. The containment also eliminates the need for a jet catcher and allows for a much longer test section. Model-generated noise is thus more easily separated from facility background using beamforming. Measurements and analysis of acoustic and aerodynamic corrections for a Kevlar-walled test section are presented and discussed, along with benchmark trailing edge noise measurements.

Devenport, William J.; Burdisso, Ricardo A.; Borgoltz, Aurelien; Ravetta, Patricio A.; Barone, Matthew F.; Brown, Kenneth A.; Morton, Michael A.

2013-08-01

119

Mode-Stirred Method Implementation for HIRF Susceptibility Testing and Results Comparison with Anechoic Method  

NASA Technical Reports Server (NTRS)

This paper describes the implementation of mode-stirred method for susceptibility testing according to the current DO-160D standard. Test results on an Engine Data Processor using the implemented procedure and the comparisons with the standard anechoic test results are presented. The comparison experimentally shows that the susceptibility thresholds found in mode-stirred method are consistently higher than anechoic. This is consistent with the recent statistical analysis finding by NIST that the current calibration procedure overstates field strength by a fixed amount. Once the test results are adjusted for this value, the comparisons with the anechoic results are excellent. The results also show that test method has excellent chamber to chamber repeatability. Several areas for improvements to the current procedure are also identified and implemented.

Nguyen, Truong X.; Ely, Jay J.; Koppen, Sandra V.

2001-01-01

120

An Absorbing Boundary Condition Based on Anechoic Absorber For EM Scattering Computation  

Microsoft Academic Search

A novel absorbing boundary condition (ABC), to be used with finite difference and finite element electromagnetic radiation and scattering problems is described. It is based on anechoic chamber absorber foam geometry, with specified complex permittivity and permeability. The advantage of this absorbing boundary is that it prevents reflections from much wider incident angles than currently used lattice termination conditions. Since

C. M. Rappaport; L. J. Bahrmasel

1992-01-01

121

The crop growth research chamber: A ground-based facility for CELSS research  

NASA Technical Reports Server (NTRS)

A ground based facility for the study of plant growth and development under stringently controlled environments is being developed by the Closed Ecological Life Support System (CELSS) program at the Ames Research Center. Several Crop Growth Research Chambers (CGRC) and laboratory support equipment provide the core of this facility. The CGRC is a closed (sealed) system with a separate recirculating atmosphere and nutrient delivery systems. The atmospheric environment, hydroponic environment, systems controls, and data acquisition are discussed.

Bubenheim, David L.

1990-01-01

122

ATMOSPHERIC CHEMISTRY OF POTENTIAL EMISSIONS FROM FUEL CONVERSION FACILITIES. A SMOG CHAMBER STUDY  

EPA Science Inventory

The atmospheric chemistry of chemical species that may be emitted from fuel conversion facilities were studied in smog chambers. Of 17 compounds assessed for ozone-forming potential, 6 compounds were selected along with a control species, propylene, for testing in the presence of...

123

Anechoic wind tunnel study of turbulence effects on wind turbine broadband noise  

Microsoft Academic Search

This paper describes recent results obtained at MIT on the experimental and theoretical modelling of aerodynamic broadband noise generated by a downwind rotor horizontal axis wind turbine. The aerodynamic broadband noise generated by the wind turbine rotor is attributed to the interaction of ingested turbulence with the rotor blades. The turbulence was generated in the MIT anechoic wind tunnel facility

B. Loyd; W. L. Harris

1995-01-01

124

Characterization of the Reverberation Chamber at the NASA Langley Structural Acoustics Loads and Transmission (SALT) Facility  

NASA Technical Reports Server (NTRS)

In 2011 the noise generating capabilities in the reverberation chamber of the Structural Acoustic Loads and Transmission (SALT) facility at NASA Langley Research Center were enhanced with two fiberglass reinforced polyester resin exponential horns, each coupled to Wyle Acoustic Source WAS-3000 airstream modulators. This report describes the characterization of the reverberation chamber in terms of the background noise, diffusivity, sound pressure levels, the reverberation times and the related overall acoustic absorption in the empty chamber and with the acoustic horn(s) installed. The frequency range of interest includes the 80 Hz to 8000 Hz one-third octave bands. Reverberation time and sound pressure level measurements were conducted and standard deviations from the mean were computed. It was concluded that a diffuse field could be produced above the Schroeder frequency in the 400 Hz one-third octave band and higher for all applications. This frequency could be lowered by installing panel diffusers or moving vanes to improve the acoustic modal overlap in the chamber. In the 80 Hz to 400 Hz one-third octave bands a successful measurement will be dependent on the type of measurement, the test configuration, the source and microphone locations and the desired accuracy. It is recommended that qualification measurements endorsed in the International Standards be conducted for each particular application.

Grosveld, Ferdinand W.

2013-01-01

125

A Large Hemi-Anechoic Enclosure for Community-Compatible Aeroacoustic Testing of Aircraft Propulsion Systems  

NASA Technical Reports Server (NTRS)

A large hemi-anechoic (absorptive walls and acoustically hard floor) noise control enclosure has been erected around a complex of test stands at the NASA Lewis Research Center in Cleveland, Ohio. This new state-of-the-art Aeroacoustic Propulsion Laboratory (APL) provides an all-weather, semisecure test environment while limiting noise to acceptable levels in surrounding residential neighborhoods. The 39.6 m (130 ft) diameter geodesic dome structure houses the new Nozzle Aeroacoustic Test Rig (NATR), an ejector-powered M = 0.3 free jet facility for acoustic testing of supersonic aircraft exhaust nozzles and turbomachinery. A multi-axis, force-measuring Powered Lift Facility (PLF) stand for testing of Short Takeoff Vertical Landing (STOVL) vehicles is also located within the dome. The design of the Aeroacoustic Propulsion Laboratory efficiently accomodates the research functions of two separate test rigs, one of which (NATR) requires a specialized environment for taking acoustic measurements. Absorptive fiberglass wedge treatment on the interior surface of the dome provides a hemi-anechoic interior environment for obtaining the accurate acoustic measurements required to meet research program goals. The APL is the first known geodesic dome structure to incorporate transmission-loss properties as well as interior absorption into a free-standing, community-compatible, hemi-anechoic test facility.

Cooper, Beth A.

1993-01-01

126

University of Missouri-Rolla cloud simulation facility - Proto II chamber  

NASA Technical Reports Server (NTRS)

The design and supporting systems for the cooled-wall expansion cloud chamber, designated Proto II, are described. The chamber is a 10-sided vertical cylinder designed to be operated with interior wall temperatures between +40 and -40 C, and is to be utilized to study microphysical processes active in atmospheric clouds and fogs. Temperatures are measured using transistor thermometers which have a range of + or - 50 C and a resolution of about + or - 0.001 C; and pressures are measured in the chamber by a differential strain gauge pressure transducer. The methods used for temperature and pressure control are discussed. Consideration is given to the chamber windows, optical table, photographic/video, optical attenuation, Mie scattering, and the scanning system for the chamber. The system's minicomputer and humidifier, sample preparation, and chamber flushing are examined.

White, Daniel R.; Carstens, John C.; Hagen, Donald E.; Schmitt, John L.; Kassner, James L.

1987-01-01

127

Ventilation characterization of the Consumer Product Safety Commission combustion test chamber facility. Final report  

SciTech Connect

The Consumer Product Safety Commission (CPSC) is evaluating pollutant emissions from kerosene and methane heaters using a test chamber. Under an interagency agreement with CPSC, the Indoor Air Quality and Ventilation Group of the National Institute of Standards and Technology (NIST) measured the air exchange rate of the chamber under various ventilation system operating conditions, the extent of air mixing within the chamber, and the interior volume of the chamber. The air exchange rate of the chamber was determined using the tracer gas decay method with sulfur hexafluoride as the tracer gas. Carbon dioxide was also used as a tracer gas in order to verify the decay rates obtained with the SF6 system; however CO2 could not be used during combustion tests. The effect of pollutant monitoring systems and combustion devices on air exchange rates was also examined. Based on multi-point concentration measurements during decays, the extent of mixing within the chamber appeared to be adequate to employ the single-zone tracer gas decay method. The interior air volume of the chamber was determined using the constant injection tracer gas technique and yielded a volume very close to the volume based on the physical dimensions of the chamber. Recommendations for an air exchange rate measurement system for the chamber and modifications to be made in order to more effectively utilize the system are made.

Dols, W.S.

1990-09-01

128

Performance of a liquid argon time projection chamber exposed to the CERN West Area Neutrino Facility neutrino beam  

SciTech Connect

We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct low-multiplicity neutrino interactions.

Arneodo, F.; Cavanna, F.; Mitri, I. De; Mortari, G. Piano [Dipartimento d Fisica e INFN, Universita' dell'Aquila, via Vetoio, L'Aquila (Italy); Benetti, P.; Borio di Tigliole, A.; Calligarich, E.; Cesana, E.; Dolfini, R.; Mauri, F.; Montanari, C.; Rappoldi, A.; Raselli, G. L.; Rubbia, C.; Terrani, M.; Vignoli, C. [Dipartimento di Fisica e INFN, Universita' di Pavia, via Bassi 6, Pavia (Italy); Bonesini, M.; Boschetti, B.; Cavalli, D.; Curioni, A. [Dipartimento di Fisica e INFN, Universita' di Milano, via Celoria 16, Milano (Italy)] (and others)

2006-12-01

129

Ventilation characterization of the Consumer Product Safety Commission combustion test chamber facility. Final report  

Microsoft Academic Search

The Consumer Product Safety Commission (CPSC) is evaluating pollutant emissions from kerosene and methane heaters using a test chamber. Under an interagency agreement with CPSC, the Indoor Air Quality and Ventilation Group of the National Institute of Standards and Technology (NIST) measured the air exchange rate of the chamber under various ventilation system operating conditions, the extent of air mixing

Dols

1990-01-01

130

DATE OF REQUEST: NVLAP LAB CODE: ECT APPLICATION ADDENDUM #2 (2008-09-12) PAGE 1 OF 3  

E-print Network

Facility Name: Anechoic chamber Room A Facility Type: Semi-anechoic chamber Test Types* Test Methods: Semi-anechoic chamber Test Types* Test Methods Reference Standards Test Condition Conducted disturbance at mains ports continuity VCCI V-3 CISPR22/EN55022 FCC method 47CFR/Part 15 Facility Name: Anechoic chamber

131

Evaluation of Radiated Transfer Functions of a Fuselage Model in an Anechoic and in a Reverberating Radio Frequency Environment  

NASA Astrophysics Data System (ADS)

In an anechoic chamber and in a reverberation chamber Radio Frequency (RF) fields are generated to illuminate a fuselage model. The fields coupled into the fuselage model are assessed. This is done by measurement and numerical computer modelling. For the numerical com- puter modelling fundamentally different approaches are applied with entirely independent model generation. The experimental and numerical results for the two different RF Environments are provided and compared. Aim is to characterize both RF environments for a radiated trans- fer function task and compare experimental and different numerical results to each other.

Rasek, G. A.; Loos, S. E.; Neubauer, M.; Junqua, I.; Schröder, A.; Pascual-Gil, E.

2012-05-01

132

Design and performance of the vacuum chambers for the undulator of the VUV FEL at the TESLA test facility at DESY  

NASA Astrophysics Data System (ADS)

Three vacuum chambers for the VUV SASE FEL undulator sections at the TESLA Test Facility (TTF) were designed, built, tested and installed. Each chamber is 4.5 m long and of 11.5 mm thick. The inner diameter of the beam pipe is 9.5 mm. The rectangular chamber profile with a width of 128 mm is used to integrate beam position monitors and steerers. This is needed to provide a good overlap between the electron and the photon beam over the entire undulator length. The chambers are built in an aluminum extrusion technology developed for the insertion device vacuum chambers of the Advanced Photon Source. After manufacturing, special processing was performed to reach low outgassing rates (<1×10 -11mbar·l/s·cm 2) and particle-free chambers. Mounting of the chambers at TTF were performed under clean room conditions better class 100.

Hahn, U.; den Hartog, P. K.; Pflüger, J.; Rüter, M.; Schmidt, G.; Trakhtenberg, E. M.

2000-05-01

133

A Concept for a Low Pressure Noble Gas Fill Intervention in the IFE Fusion Test Facility (FTF) Target Chamber  

SciTech Connect

An engineering evaluation has been initiated to investigate conceptual engineering methods for implementing a viable gas shield strategy in the Fusion Test Facility (FTF) target chamber. The employment of a low pressure noble gas in the target chamber to thermalize energetic helium ions prior to interaction with the wall could dramatically increase the useful life of the first wall in the FTF reactor1. For the purpose of providing flexibility, two target chamber configurations are addressed: a five meter radius sphere and a ten meter radius sphere. Experimental studies at Nike have indicated that a low pressure, ambient gas resident in the target chamber during laser pulsing does not appear to impair the ability of laser light from illuminating targets2. In addition, current investigations into delivering, maintaining, and processing low pressure gas appear to be viable with slight modification to current pumping and plasma exhaust processing technologies3,4. Employment of a gas fill solution for protecting the dry wall target chamber in the FTF may reduce, or possibly eliminate the need for other attenuating technologies designed for keeping He ions from implanting in first wall structures and components. The gas fill concept appears to provide an effective means of extending the life of the first wall while employing mostly commercial off the shelf (COTS) technologies. Although a gas fill configuration may provide a methodology for attenuating damage inflicted on chamber surfaces, issues associated with target injection need to be further analyzed to ensure that the gas fill concept is viable in the integrated FTF design5. In the proposed system, the ambient noble gas is heated via the energetic helium ions produced by target detonation. The gas is subsequently cooled by the chamber wall to approximately 800oC, removed from the chamber, and processed by the chamber gas processing system (CGPS). In an optimized scenario of the above stated concept, the chamber wall acts as the primary heat exchanger. During removal, gas is pumped through the laser ports by turbo molecular-drag pumps (TM-DP). For the purpose of reducing organic based lubricants and seals, a magnetically levitated TM-DP is being investigated with pump manufacturers. Currently, magnetically levitated turbo molecular pumps are commercially available. The pumps will be exposed to thermal loads and ionizing radiation (tritium, Ar-41, post detonation neutrons). Although the TM-DP's will be subjected to these various radiations, current designs for similar pumping devices have been hardened and have the ability of locating control electronics in remote radiation shielded enclosures4. The radiation hardened TM-DP's will be 5 required to operate with minimal maintenance for periods of up to 18 continuous months. As part of this initial investigation for developing a conceptual engineering strategy for a gas fill solution, commercial suppliers of low pressure gas pumping systems have been contacted and engaged in this evaluation. Current technology in the area of mechanical pumping systems indicates that the development of a robust pumping system to meet the requirements of the FTF gas fill concept is within the limits of COTS equipment3,4.

Gentile, C. A.; Blanchard, W. R.; Kozub, T. A.; Aristova, M.; McGahan, C.; Natta, S.; Pagdon, K.; Zelenty, J.

2010-01-14

134

Noise control of a model scale jet engine component test facility  

SciTech Connect

Noise control is a fundamental design requirement in a test facility used for research and development of noise suppression devices and test techniques for modern fan jet engines. For every type of test in the facility, three aspects of noise control must be considered: noise exchange between the community and the test chamber, the acoustic characteristics of the chamber, and the methodology of the experiment. Boeing has designed and built a large anechoic test chamber (LTC) for engine component noise tests, with special emphasis on these three areas of noise control. Primary design goals were established by a need for high quality model scale jet engine exhaust studies, with minimum noise interaction with nearby communities. This paper discusses the noise control aspects of the LTC for both jet exhaust and fan noise testing.

Simcox, C.D.

1982-01-01

135

Mars and Lunar Vacuum Chamber Testing Facilities and Vacuum Rated Drill Systems  

NASA Astrophysics Data System (ADS)

Martian and Lunar low pressure and vacuum conditions, respectively, greatly affect the performance of the drilling mechanics and drill hardware. For this reason, it is imperative to test planetary sampling and coring drills under these specific environments. Honeybee Robotics acquired an 11ft vacuum chamber that is currently being used to test drills to 1m depth and more. A separate cooling system is used to maintain low temperature of planetary analog formations such as ice, soil, icy-soils, and rocks. The low temperature increases the strength of these formations and in turn reduces drilling efficiency. The chamber also has a numerous feed troughs that can be used to transfer thermal data from thermocouples embedded inside the drilled sample, and the drill bits. The thermal data is useful to determine the temperature the sample reaches during the drilling process. The drill systems include rotary, rotary-percussive, and rotary-sonic. The latter two, in particular, offer superior performance in hard formations due to impacts and/or vibrations that enhance penetration rate. All the drill systems are vacuum rated and hence can be used as test platforms for vacuum testing.

Zacny, K.; Paulsen, G.; Craft, J.; Maksymuk, M.; Santoro, C.; Wilson, J.

2009-12-01

136

Mdt Chamber Ageing Test at Enea Casaccia Neutron and Gamma Facilities  

NASA Astrophysics Data System (ADS)

The Monitored Drift Tubes (MDT) are used for precision tracking in the muon spectrometer of the ATLAS experiment. They have to cope with a counting rate reaching 500 Hz/cm2 mostly due to photon and neutron background in the experimental hall which corresponds to an accumulated charge of 0.6 C/cm per wire in 10 years of LHC operation at the nominal luminosity of 1034 cm-2s-1. The neutron flux is expected to be about 5 kHz/cm2, corresponding to a counting rate of 2.5 Hz/cm2. MDTs ageing studies have been performed at the ENEA-Casaccia Research Center (Italy) irradiating a test chamber with neutrons up to an integrated flux of 2.4·1012 neutrons/cm2 and with photons up to an integrated charge of 4.8 C/cm.

Avolio, G.; Branchini, P.; di Luise, S.; Graziani, E.; La Rotonda, L.; Mazzotta, C.; Meoni, E.; Passeri, A.; Petrucci, F.; Policicchio, A.; Salvatore, D.; Schioppa, M.; Tonazzo, A.

2006-04-01

137

Venus Pressure Chamber: A Small Testing Facility Available to the Community  

NASA Technical Reports Server (NTRS)

Venus is an inhospitable planet where the surface mean. temperature is approximately 740K and the global mean pressure is approximately 95 bars. The atmosphere is comprised mostly of CO2 (approximately 96.5%) and N2 (approximately3.5%) with trace amounts of CO and other reactive gases. Although Venus is very similar in size and mass with the Earth and is Earth's nearest planetary neighbor, it has not received many visitors from Earth, especially those that can land on the surface. The challenge most often cited for this scarcity of surface probes is the workability/survivability of instruments and equipment in Venus' harsh environment. In order to overcome this obstacle, a small pressure chamber has been acquired for use by the scientific community. It is housed at Goddard Space. Flight Center in Maryland and is available to the community for testing of small flight components, instruments and short-term experiments that require high temperatures and pressures.

Johnson, Natasha M.; Wegel, D. C.

2011-01-01

138

Archiving Quality Control Tests in the PHENIX Resistive Plate Chamber Assembly Facility  

NASA Astrophysics Data System (ADS)

The PHENIX collaboration at RHIC studies polarized proton-proton collisions to better understand the spin structure of the proton. PHENIX is in the process of upgrading the muon trigger to improve our capabilities of selecting the muons from the decay of W-bosons which are produced more readily at a high transverse momentum than other muon sources. By triggering on single, high transverse momentum muons, new observations on the spin asymmetries of a proton can be obtained. The trigger upgrade will consist of four stations of Resistive Plate Chambers (RPCs), with stations on each side of the interaction region. Each RPC consists of two Bakelite gas gaps, a copper signal plane, an aluminum case, and several layers of mylar and copper. With all of these parts comes the need to archive the manufacturing and quality assurance information along with test results performed on them. This information is kept in a Postgresql Database in the RPC factory and is maintained, modified, and read out through several PHP web pages. A new output page has been produced that will make all of this information much more accessible. This poster will focus on what data is archived, how it is stored, and how it can be easily retrieved and put to use.

Andrews, Keller

2009-10-01

139

The V-3 contamination test of the chamber A facility and a subsequent cryogenic/vacuum study of the V-3 test quartz crystal microbalance  

NASA Technical Reports Server (NTRS)

The areas of orbital and ground contamination of flight experiment hardware have been well established. This report relates directly to results of vacuum chamber testing for the ground evaluation of flight experiment hardware performance. First, the data obtained during the V-3 contamination testing in the Johnson Space Center's Chamber A space simulation test facility are presented. Second, during the V-3 contamination tests, the MSFC Space Sciences Laboratory's quartz crystal microbalance exhibited two periods of anomalous readings. Therefore, a subsequent small chamber tests was conducted in a controlled cryogenic/vacuum environment. The objective was to reproduce with known parameters the anomalous behavior patterns of the V-3 test data. Analyses of the anomalous readings are made on the basis of these tests. Additionally, as a by-product of the small chamber tests, calibration curves then existing for the quartz crystal microbalance were empirically extended, and certain data-formatting aids were documented.

Moore, W. W., Jr.; Tashbar, P. W.

1973-01-01

140

Anechoic wind tunnel study of turbulence effects on wind turbine broadband noise  

NASA Astrophysics Data System (ADS)

This paper describes recent results obtained at MIT on the experimental and theoretical modelling of aerodynamic broadband noise generated by a downwind rotor horizontal axis wind turbine. The aerodynamic broadband noise generated by the wind turbine rotor is attributed to the interaction of ingested turbulence with the rotor blades. The turbulence was generated in the MIT anechoic wind tunnel facility with the aid of biplanar grids of various sizes. The spectra and the intensity of the aerodynamic broadband noise have been studied as a function of parameters which characterize the turbulence and of wind turbine performance parameters. Specifically, the longitudinal integral scale of turbulence, the size scale of turbulence, the number of turbine blades, and free stream velocity were varied. Simultaneous measurements of acoustic and turbulence signals were made. The sound pressure level was found to vary directly with the integral scale of the ingested turbulence but not with its intensity level. A theoretical model based on unsteady aerodynamics is proposed.

Loyd, B.; Harris, W. L.

1995-05-01

141

Anechoic wind tunnel study of turbulence effects on wind turbine broadband noise  

NASA Technical Reports Server (NTRS)

This paper describes recent results obtained at MIT on the experimental and theoretical modelling of aerodynamic broadband noise generated by a downwind rotor horizontal axis wind turbine. The aerodynamic broadband noise generated by the wind turbine rotor is attributed to the interaction of ingested turbulence with the rotor blades. The turbulence was generated in the MIT anechoic wind tunnel facility with the aid of biplanar grids of various sizes. The spectra and the intensity of the aerodynamic broadband noise have been studied as a function of parameters which characterize the turbulence and of wind turbine performance parameters. Specifically, the longitudinal integral scale of turbulence, the size scale of turbulence, the number of turbine blades, and free stream velocity were varied. Simultaneous measurements of acoustic and turbulence signals were made. The sound pressure level was found to vary directly with the integral scale of the ingested turbulence but not with its intensity level. A theoretical model based on unsteady aerodynamics is proposed.

Loyd, B.; Harris, W. L.

1995-01-01

142

Inlet turbulence and fan noise measured in an anechoic wind tunnel and statically with an inlet flow control device  

NASA Technical Reports Server (NTRS)

Turbulence and acoustic measurements were taken in the NASA-Lewis anechoic wind tunnel - a facility which has demonstrated the blade passage tone cutoff phenomena with forward velocity. Turbulence data were taken in a subsonic inlet at various fan speeds under static and forward velocity conditions. A honeycomb/screen flow control device was placed over the inlet during static tests to modify the inflow in an attempt to simulate flight conditions. Acoustic levels of the blade passage tone along with transverse turbulence intensities were reduced with forward velocity. The flow control device reduced the blade passage tone to an intermediate level between those levels associated with static and forward velocity operation.

Shaw, L. M.; Woodward, R. P.; Glaser, F. W.; Dastoli, B. J.

1977-01-01

143

Simulation of flight-type engine fan noise in the NASA-Lewis 9 x 15 anechoic wind tunnel  

NASA Technical Reports Server (NTRS)

A major problem in the measurement of aircraft engine fan noise is the difficulty of simulating, in a ground-based facility, the noise that occurs during flight. Flight-type noise as contrasted to the usual ground-static test noise exhibits substantial reductions in both (1) the time unsteadiness of tone noise and (2) the mean level of tones calculated to be nonpropagating or cut-off. A model fan designed with cut-off of the fundamental tone was acoustically tested in the anechoic wind tunnel under both static and tunnel flow conditions. The properties that characterize flight-type noise were progressively simulated with increasing tunnel flow. The distinctly lobed directivity pattern of propagating rotor/stator interaction modes was also observed. The results imply that the excess noise attributed to the ingestion of the flow disturbances that prevail near most static test facilities was substantially reduced with tunnel flow. The anechoic wind tunnel appears to be a useful facility for applied research on aircraft engine fan noise under conditions of simulated flight.

Heidmann, M. F.; Dietrich, D. A.

1976-01-01

144

CFD Simulation on the J-2X Engine Exhaust in the Center-Body Diffuser and Spray Chamber at the B-2 Facility  

NASA Technical Reports Server (NTRS)

A computational fluid dynamic (CFD) code is used to simulate the J-2X engine exhaust in the center-body diffuser and spray chamber at the Spacecraft Propulsion Facility (B-2). The CFD code is named as the space-time conservation element and solution element (CESE) Euler solver and is very robust at shock capturing. The CESE results are compared with independent analysis results obtained by using the National Combustion Code (NCC) and show excellent agreement.

Wang, Xiao-Yen; Wey, Thomas; Buehrle, Robert

2009-01-01

145

Classification of heart valve sounds from experiments in an anechoic water tank  

SciTech Connect

In vivo studies in both sheep and humans were plagued by a number of problems including movement artifacts, biological noise, low signal-to-noise ratio (SNR), chest-wall reverberation, and limited bandwidth recordings as discussed by [1]. To overcome these problems it was decided to record heart valve sounds under controlled conditions deep in an anechoic water tank, free from reverberation noise. The main goal of this experiment was to obtain measurements of ''pure'' heart valve sounds free of the scattering effects of the body. Experiments were conducted at the Transdec facility in San Diego [2]. We used a high quality hydrophone together with a wide-band data acquisition system [2]. We recorded sounds from 100 repetitions of the opening-closing cycles on each of 50 different heart valves, including 21 SLS valves and 29 intact valves. The power spectrum of the opening and closing phases of each cycle were calculated and outlier spectra removed as described by Candy [2]. In this report, we discuss the results of our classification of the heart valve sound measurements. The goal of this classification task was to apply the fundamental classification algorithms developed for the clinical data in 1994 and 1996 to the measurements from the anechoic water tank. From the beginning of this project, LLNL's responsibility has been to process and classify the heart valve sounds. For this experiment, however, we processed both the opening sounds and closing sounds for comparison purposes. The results of this experiment show that the classifier did not perform well because of low signal-to-noise ratio and excessive variability in signal power from beat-to-beat for a given valve.

Axelrod, M C; Clark, G A; Scott, D

1999-06-01

146

Classification of heart valve sounds from experiments in an anechoic water tank  

SciTech Connect

In vivo studies in both sheep and humans were plagued by a number of problems including movement artifacts, biological noise, low signal-to-noise ratio (SNR), chest-wall reverberation, and limited bandwidth recordings as discussed by [1]. To overcome these problems it was decided to record heart valve sounds under controlled conditions deep in an anechoic water tank, free from reverberation noise, including surface reflections. Experiments were conducted in a deep water tank at the Transdec facility in San Diego, which satisfies these requirements. The Transdec measurements are free of reverberations, but not totally free of acoustic and electrical noise. We used a high quality hydrophone together with a wide-band data acquisition system [2]. We recorded sounds from 100 repetitions of the opening-closing cycles on each of 50 different heart valves, including 21 SLS valves and 29 intact valves. The power spectrum of the opening and closing phases of each cycle were calculated and outlier spectra removed as described by Candy [2]. In this report, we discuss the results of our classification of the heart valve sound measurements. The goal of this classification task was to apply the fundamental classification algorithms developed for the clinical data in 1994 and 1996 to the measurements from the anechoic water tank. From the beginning of this project, LLNL's responsibility has been to process and classify the heart valve opening sounds. For this experiment, however, we processed both the opening sounds and closing sounds for comparison purposes. The results of this experiment show that the classifier did not perform well. We believe this is because of low signal-to-noise ratio and excessive variability in signal power from beat-to-beat for a given valve.

Axelrod, M C; Clark, G A; Scott, D

1999-06-01

147

Processing of Prosthetic Heart Valve Sounds from Anechoic Tank Measurements  

SciTech Connect

People with serious cardiac problems have had their life span extended with the development of the prosthetic heart valve. However, the valves operate continuously at approximately 39 million cycles per year and are therefore subject to structural failures either by faulty design or material fatigue. The development of a non-invasive technique using an acoustic contact microphone and sophisticated signal processing techniques has been proposed and demonstrated on limited data sets. In this paper we discuss an extension of the techniques to perform the heart valve tests in an anechoic like. Here the objective is to extract a ''pure'' sound or equivalently the acoustical vibration response of the prosthetic valves in a quiet environment. The goal is to demonstrate that there clearly exist differences between values which have a specific mechanical defect known as single leg separation (SLS) and non-defective valves known as intact (INT). We discuss the signal processing and results of anechoic acoustic measurements on 50 prosthetic valves in the tank. Finally, we show the results of the individual runs for each valve, point out any of the meaningful features that could be used to distinguish the SLS from INT and summarize the experiments.

Candy, J V; Meyer, A W

2001-03-20

148

Development of the mini-ionization chamber for high-dose real-time monitoring inside a gamma irradiation facility  

Microsoft Academic Search

A cylindrical ionization chamber of 0.9 cm3 has been developed for high-doses real-time monitoring during the sample irradiation at a static position in a 60Co gamma industrial plant, with about 25.9 PBq (700 kCi). Nitrogen gas at pressure of 1 bar was utilized to fill the ionization chamber for which an appropriate configuration was determined, to be used as a

Ary de A. Rodrigues; Jose M. Vieira; Margarida M. Hamada

2003-01-01

149

Development of the mini ionization chamber for high dose monitoring on line inside a gamma irradiation facility  

Microsoft Academic Search

A cylindrical ionization chamber of 0.9 cm3 has been developed for monitoring high doses on line during the sample irradiation at a static position in a 60Co gamma industrial plant, with about 25.9 PBq (700 kCi). Nitrogen gas at pressure of 1 bar was utilized to fill the ionization chamber and to determine an appropriate configuration to be used as

Jose M. Vieira; Margarida M. Hamada

2002-01-01

150

Capabilities, Design, Construction and Commissioning of New Vibration, Acoustic, and Electromagnetic Capabilities Added to the World's Largest Thermal Vacuum Chamber at NASA's Space Power Facility  

NASA Technical Reports Server (NTRS)

NASA s human space exploration plans developed under the Exploration System Architecture Studies in 2005 included a Crew Exploration Vehicle launched on an Ares I launch vehicle. The mass of the Crew Exploration Vehicle and trajectory of the Ares I coupled with the need to be able to abort across a large percentage of the trajectory generated unprecedented testing requirements. A future lunar lander added to projected test requirements. In 2006, the basic test plan for Orion was developed. It included several types of environment tests typical of spacecraft development programs. These included thermal-vacuum, electromagnetic interference, mechanical vibration, and acoustic tests. Because of the size of the vehicle and unprecedented acoustics, NASA conducted an extensive assessment of options for testing, and as result, chose to augment the Space Power Facility at NASA Plum Brook Station, of the John H. Glenn Research Center to provide the needed test capabilities. The augmentation included designing and building the World s highest mass capable vibration table, the highest power large acoustic chamber, and adaptation of the existing World s largest thermal vacuum chamber as a reverberant electromagnetic interference test chamber. These augmentations were accomplished from 2007 through early 2011. Acceptance testing began in Spring 2011 and will be completed in the Fall of 2011. This paper provides an overview of the capabilities, design, construction and acceptance of this extraordinary facility.

Motil, Susan M.; Ludwiczak, Damian R.; Carek, Gerald A.; Sorge, Richard N.; Free, James M.; Cikanek, Harry A., III

2011-01-01

151

Directional loudness in an anechoic sound field, head-related transfer functions, and binaural summation.  

PubMed

The effect of sound incidence angle on loudness was investigated using real sound sources positioned in an anechoic chamber. Eight normal-hearing listeners produced loudness matches between a frontal reference location and seven sources placed at other directions, both in the horizontal and median planes. Matches were obtained via a two-interval, adaptive forced-choice (2AFC) procedure for three center frequencies (0.4, 1, and 5 kHz) and two overall levels (45 and 65 dB SPL). The results showed that loudness is not constant over sound incidence angles, with directional sensitivity varying over a range of up to 10 dB, exhibiting considerable frequency dependence, but only minor effects of overall level. The pattern of results varied substantially between subjects, but was largely accounted for by variations in individual head-related transfer functions. Modeling of binaural loudness based on the at-ear signals favored a sound-power summation model, according to which the maximum binaural gain is only 3 dB, over competing models based on larger gains, or on the summation of monaural loudness indices. PMID:16708953

Sivonen, Ville Pekka; Ellermeier, Wolfgang

2006-05-01

152

Flow chamber  

DOEpatents

A flow chamber having a vacuum chamber and a specimen chamber. The specimen chamber may have an opening through which a fluid may be introduced and an opening through which the fluid may exit. The vacuum chamber may have an opening through which contents of the vacuum chamber may be evacuated. A portion of the flow chamber may be flexible, and a vacuum may be used to hold the components of the flow chamber together.

Morozov, Victor (Manassas, VA)

2011-01-18

153

Anechoic chamber having multi-layer electromagnetic wave absorbers of sintered ferrite and ferrite composite membrane  

Microsoft Academic Search

The structure of the multi-layer electromagnetic wave absorber composed of sintered ferrite and ferrite composite membrane is proposed to improve radiowave absorbing characteristics. The absorption characteristics of the multi-layer absorber can be largely extended compared with the single sintered ferrite layer. Moreover, it is shown that the site attenuation characteristics satisfy the FCC standard for 3 m and 10 m

K. Naito; Tetsuya Mizumoto; Michiharu Takahashi; Sumio Kunieda

1994-01-01

154

Realization of compact semi- and fully anechoic chambers using a new developed composite absorber  

Microsoft Academic Search

The shape of a composite absorber consisting of ferrite and dielectric lossy material was investigated to reduce the length of the absorber and improve the reflection coefficient in the low frequency range by effectively changing the cross section of the dielectric lossy materials towards the direction of the length. It was found that the most suitable change of cross section

Ken Ishino; Takao Morikawa; Toshifumi Saito; Yasuo Hashimoto; Yasutaka Shimizu

1994-01-01

155

A parametric UWB propagation channel estimation and its performance validation in an anechoic chamber  

Microsoft Academic Search

This paper presents an ultrawide-band (UWB) channel sounding scheme with a parametric channel estimation to seek accurate probing of the propagation channel. The channel sounder consists of a vector network analzer and synthetic array to measure spatial transfer functions. The measured data are then applied to a maximum-likelihood (ML)-based estimator. The concepts implemented in the ML-based parametric channel estimation are:

Katsuyuki Haneda; Jun-Ichi Takada; Takehiko Kobayashi

2006-01-01

156

Compact antenna test range without reflector edge treatment and RF anechoic chamber  

Microsoft Academic Search

There are several types of CATRs (compact antenna test ranges) used in antenna-pattern measurements. An offset reflector is generally used to generate the quiet zone of a CATR. Serrated edges, rolled edges, or R-cards are generally chosen along the reflector's edge to reduce the edge-diffraction field inside the quiet zone of the CATR. In order to reduce stray signals from

Dau-Chyrh Chang; Chao-Hsiang Liao; Chih-Chun Wu

2004-01-01

157

Analysis of compact electromagnetic anechoic chamber performance using finite difference time domain methods  

Microsoft Academic Search

The feasibility of modeling compact range performance using the FDTD (finite difference time domain) method is discussed. The advantages of the FDTD method, such as excitation waveform, material, and geometric generality are considered. The limitations, including staircasing errors (which can be reduced or eliminated at the expense of increased computation) and a maximum computation frequency based on computer resource limitations,

R. Luebbers; D. Steich; D. Ryan; K. Kunz

1991-01-01

158

Modeling of RF Absorber for Application in the Design of Anechoic Chamber  

Microsoft Academic Search

Abstract—A proper model of RF absorber must be developed based on information such as absorber reflectivity, in magnitude and phase, for various angles of incidence, and for parallel and perpendicular polarizations. Unfortunately, these data are not available due to the practical limitations of the test fixtures to measure the RF absorber performance. Manufacturer data sheets normally specify only the magnitude

B.-K. Chung; H.-T. Chuah

2003-01-01

159

Oblique scattering from lossy periodic surfaces with applications to anechoic chamber absorbers  

Microsoft Academic Search

Plane wave scattering from lossy, periodic surfaces with periodicity in one direction is considered for arbitrary polarization and incidence angles. The material is assumed to be homogeneous and characterized by complex values of permittivity and permeability. Muller-type coupled integral equations are derived for the surface electric and magnetic currents. The power reflection coefficient is defined in terms of the scattered

Ramakrishna Janaswamy

1992-01-01

160

A method of pattern measurement to cancel reflection waves in anechoic chamber  

Microsoft Academic Search

In the paper, we have shown that averaging the radiation patterns over several distances between two antennas is useful in order to reduce the influence of reflection waves, using simulation software FEKO. In the conditions with and without reflection waves we simulate the radiation patterns of the biconical antenna (the operation band is from 30 MHz to 300 MHz) in

Mio. Nagatoshi; M. Hirose; H. Tanaka; S. Kurokawa; H. Morishita

2008-01-01

161

Indoor time domain RCS measurements and ISAR imaging without anechoic chamber  

Microsoft Academic Search

RCS measuring in time domain opens wide possibilities for interesting applications. Using of the short impulses as test signals enables to do RCS measurements in wide frequency band. In this paper, time domain method is presented which let to overcome many measurement problems: signal leakage through antennas, occasional reflection from the walls, and ceilings of the room. It leads to

B. Levitas; J. Matuzas

2004-01-01

162

Comparison of particle velocity and sound pressure measurements in anechoic and medfly bioassay chambers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Many insects without tympanal ears do not perceive the pressure component of sound, but instead have movement receptors (usually small hairs on body or antennae) that are sensitive to sound particle velocity -- oscillations of air particles in the sound field. In our laboratory, efforts to develop...

163

Sound absorption of a rib-stiffened plate covered by anechoic coatings.  

PubMed

Underwater vehicles are often equipped with anechoic coatings to absorb the sound waves of active sonar and attenuate the noise emitted from the vessels. Rubber layers with periodically distributed air cavities are widely used as anechoic coatings. In this paper, the sound absorption of anechoic coatings embedded with doubly periodic cavities and backed with periodically rib-stiffened plates is investigated using a finite element method (FEM) with Bloch-periodic boundary conditions. Numerical results given by the FEM are compared with those of a simplified transfer impedance approach to explain the shifting of the main absorption peak. Further a simplified FEM approach, which reduces calculation time significantly and maintains the reasonable accuracy, is proposed for a comparison. The results indicate that the plate and the ribs can have significant impacts on the absorption performance of anechoic coatings, especially at low frequencies. PMID:25786965

Fu, Xinyi; Jin, Zhongkun; Yin, Yao; Liu, Bilong

2015-03-01

164

A Robust Method to Count and Locate Audio Sources in a Stereophonic Linear Anechoic Mixture  

Microsoft Academic Search

We propose a new method, called DEMIX anechoic, to estimate the mixing conditions, i.e. number of audio sources plus attenuation and time delay of each sources, in an underdetermined anechoic mixture. The method relies on the assumption that in the neighborhood of some time-frequency points, only one source contributes to the mixture. Such time-frequency points, located with a local confidence

Simon Arberet; Remi Gribonval; F. Bimbot

2007-01-01

165

Simulation of Flight-Type Engine Fan Noise in the NASA-Lewis 9X15 Anechoic Wind Tunnel  

NASA Technical Reports Server (NTRS)

Flight type noise as contrasted to the usual ground static test noise exhibits substantial reductions in the time unsteadiness of tone noise, and in the mean level of tones calculated to be nonpropagating or cut-off. A model fan designed with cuttoff of the fundamental tone was acoustically tested in the anechoic wind tunnel under both static and tunnel flow conditions. The properties that characterize flight type noise were progressively simulated with increasing tunnel flow. The distinctly lobed directivity pattern of propagating rotor/stator interaction modes was also observed. Excess noise attributed to the ingestion of the flow disturbances that prevail near most static test facilities is substantially reduced with tunnel flow.

Heidmann, M. F.; Dietrich, D. A.

1976-01-01

166

Ultra-light duct for an anechoic wind tunnel  

NASA Technical Reports Server (NTRS)

A tunnel ultra-light (or TUL) is a duct composed of acoustically transparent cloth designed to transform an open-jet wind tunnel into a closed-jet wind tunnel. This concept is of interest (a priori) for anechoic wind tunnels because it improves the aerodynamic quality without hindering the measurement of sound in the far field. A full scale device designed for the 3 m diameter test section of CEPRA 19 was described. The apparatus installation did not develop any significant problems, and the mechanical support turned out to be excellent. Aerodynamic and acoustic tests are discussed. Certain imperfections in the installation as tested - instabilities above 25 m/s and acceptable cloth transmission up to 4kHz were revealed. The system as tested could eventually be used in certain applications, for example, in ground based transport. However, the concept of TUL must be developed further to arrive at a reliable mechanism for use in a large number of applications.

Lambourion, J.; Lewy, S.; Papirnyk, O.; Rahier, G.; Remandet, J.-N.

1989-01-01

167

Binaural Simulation Experiments in the NASA Langley Structural Acoustics Loads and Transmission Facility  

NASA Technical Reports Server (NTRS)

A location and positioning system was developed and implemented in the anechoic chamber of the Structural Acoustics Loads and Transmission (SALT) facility to accurately determine the coordinates of points in three-dimensional space. Transfer functions were measured between a shaker source at two different panel locations and the vibrational response distributed over the panel surface using a scanning laser vibrometer. The binaural simulation test matrix included test runs for several locations of the measuring microphones, various attitudes of the mannequin, two locations of the shaker excitation and three different shaker inputs including pulse, broadband random, and pseudo-random. Transfer functions, auto spectra, and coherence functions were acquired for the pseudo-random excitation. Time histories were acquired for the pulse and broadband random input to the shaker. The tests were repeated with a reflective surface installed. Binary data files were converted to universal format and archived on compact disk.

Grosveld, Ferdinand W.; Silcox, Richard (Technical Monitor)

2001-01-01

168

Exposure chamber  

DOEpatents

A chamber for exposing animals, plants, or materials to air containing gases or aerosols is so constructed that catch pans for animal excrement, for example, serve to aid the uniform distribution of air throughout the chamber instead of constituting obstacles as has been the case in prior animal exposure chambers. The chamber comprises the usual imperforate top, bottom and side walls. Within the chamber, cages and their associated pans are arranged in two columns. The pans are spaced horizontally from the walls of the chamber in all directions. Corresponding pans of the two columns are also spaced horizontally from each other. Preferably the pans of one column are also spaced vertically from corresponding pans of the other column. Air is introduced into the top of the chamber and withdrawn from the bottom. The general flow of air is therefore vertical. The effect of the horizontal pans is based on the fact that a gas flowing past the edge of a flat plate that is perpendicular to the flow forms a wave on the upstream side of the plate. Air flows downwardly between the chamber walls and the outer edges of the pan. It also flows downwardly between the inner edges of the pans of the two columns. It has been found that when the air carries aerosol particles, these particles are substantially uniformly distributed throughout the chamber.

Moss, Owen R. (Kennewick, WA)

1980-01-01

169

A time domain spherical near-field measurement facility for UWB antennas employing a hardware gating technique  

NASA Astrophysics Data System (ADS)

A spherical near-field antenna measurement facility employing a time domain hardware gating technique is presented. On-off keyed sinusoidal impulses are used as stimuli requiring wideband antennas with a bandwidth in excess of 400 MHz. The received signal is evaluated in the time interval after reaching the steady state and before multipath components arising in the non-ideal anechoic chamber distort the signal. An application specific pulse generator synthesizing sinusoidal impulses with a sub-nanosecond settling time and a low-cost equivalent time (ET) sampling receiver developed and optimized for this particular purpose are described. Measurement results of typical ultra-wideband (UWB) antennas show a significant improvement of the measured antenna pattern compared to conventional techniques.

Blech, M. D.; Leibfritz, M. M.; Hellinger, R.; Geier, D.; Maier, F. A.; Pietsch, A. M.; Eibert, T. F.

2010-10-01

170

Wire chamber  

DOEpatents

A wire chamber or proportional counter device, such as Geiger-Mueller tube or drift chamber, improved with a gas mixture providing a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor.

Atac, Muzaffer (Wheaton, IL)

1989-01-01

171

Design, Characterization, and Optimization of a Broadband Mini Exposure Chamber for Studying Catecholamine Release From Chromaffin Cells Exposed to Microwave Radiation: Finite-Difference Time-Domain Technique  

Microsoft Academic Search

A free-space in vitro exposure system for identifying specific microwave (MW) parameters in the frequency range of 1-6 GHz that can induce nonthermal effects on exocytosis, which is the process by which neurotransmitter release occurs, has been designed, constructed, characterized, and optimized. The exposure system is placed within an anechoic chamber and incorporates continuous online monitoring of basal and stimulated

Jihwan Yoon; I. Chatterjee; D. McPherson; G. L. Craviso

2006-01-01

172

A High-Flow Turbulent Cloud Chamber  

Microsoft Academic Search

A large laboratory facility (cloud chamber) has been built to study cloud formation under reproducible conditions. The chamber was designed to assess the influence of anthropogenic aerosols on the microstructure of marine clouds in coastal Western Europe. For this reason the supersaturations in the chamber are low, in the order of 0.1%, typical for coastal marine stratus. The very large

A. Khlystou; G. P. A. Kos; H. M. ten Brink

1996-01-01

173

Improved low-frequency performance of pyramid-cone absorbers for application in semi-anechoic chambers  

Microsoft Academic Search

A mathematical model, developed by the authors to describe the low-frequency reflection properties of arrays of pyramid-cone absorbers, is used to improve the design of these cones in the range of 30 to 300 MHz. The model shows that at frequencies such that the transverse spacing of the cones is small compared to a wavelength, a reflecting wave is not

Edward F. Kuester; Christopher L. Holloway

1989-01-01

174

Backscattering analysis of flat plate and dihedral corner reflectors using PO and comparison with RCS measurements in anechoic chamber  

Microsoft Academic Search

Physical Optics (PO) is used to calculate Radar Cross Section (RCS) of flat plate and dihedral corner reflectors. The numerical results obtained via simulation are used to compare the RCS measured for these targets recovered and non-recovered with Radar Absorbing Materials (RAM). All simulations and experiments are effectuated in a frequency of 10 GHz. Experimental measurements using Radar Cross Section

L. A. Andrade; E. L. Nohara; G. G. Peixoto; M. C. Rezende; I. M. Martin

2003-01-01

175

Multipath effects in semi-anechoic chambers at low frequencies: a simplified prediction model based on image theory  

Microsoft Academic Search

The multipath effects due to radiating sources inside a shielded room can not be neglected when the frequency of the harmonic components of the electromagnetic field are below the frequency threshold of the absorber lined walls. This paper deals with the prediction of the total radiated field by an electric dipole source inside a shielded room, taking into account the

A. Orlandi

1996-01-01

176

Chamber B Thermal/Vacuum Chamber: User Test Planning Guide  

NASA Technical Reports Server (NTRS)

Test process, milestones and inputs are unknowns to first-time users of Chamber B. The User Test Planning Guide aids in establishing expectations for both NASA and non-NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware/software developers. It is intended to assist their test engineering personnel in test planning and execution. Material covered includes a roadmap of the test process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, test article interfaces, and inputs necessary to define test scope, cost, and schedule are included as an appendix to the guide.

Montz, Mike E.

2012-01-01

177

Research and test facilities  

NASA Technical Reports Server (NTRS)

A description is given of each of the following Langley research and test facilities: 0.3-Meter Transonic Cryogenic Tunnel, 7-by 10-Foot High Speed Tunnel, 8-Foot Transonic Pressure Tunnel, 13-Inch Magnetic Suspension & Balance System, 14-by 22-Foot Subsonic Tunnel, 16-Foot Transonic Tunnel, 16-by 24-Inch Water Tunnel, 20-Foot Vertical Spin Tunnel, 30-by 60-Foot Wind Tunnel, Advanced Civil Transport Simulator (ACTS), Advanced Technology Research Laboratory, Aerospace Controls Research Laboratory (ACRL), Aerothermal Loads Complex, Aircraft Landing Dynamics Facility (ALDF), Avionics Integration Research Laboratory, Basic Aerodynamics Research Tunnel (BART), Compact Range Test Facility, Differential Maneuvering Simulator (DMS), Enhanced/Synthetic Vision & Spatial Displays Laboratory, Experimental Test Range (ETR) Flight Research Facility, General Aviation Simulator (GAS), High Intensity Radiated Fields Facility, Human Engineering Methods Laboratory, Hypersonic Facilities Complex, Impact Dynamics Research Facility, Jet Noise Laboratory & Anechoic Jet Facility, Light Alloy Laboratory, Low Frequency Antenna Test Facility, Low Turbulence Pressure Tunnel, Mechanics of Metals Laboratory, National Transonic Facility (NTF), NDE Research Laboratory, Polymers & Composites Laboratory, Pyrotechnic Test Facility, Quiet Flow Facility, Robotics Facilities, Scientific Visualization System, Scramjet Test Complex, Space Materials Research Laboratory, Space Simulation & Environmental Test Complex, Structural Dynamics Research Laboratory, Structural Dynamics Test Beds, Structures & Materials Research Laboratory, Supersonic Low Disturbance Pilot Tunnel, Thermal Acoustic Fatigue Apparatus (TAFA), Transonic Dynamics Tunnel (TDT), Transport Systems Research Vehicle, Unitary Plan Wind Tunnel, and the Visual Motion Simulator (VMS).

1993-01-01

178

Performance of the high speed anechoic wind tunnel at Lyon University  

NASA Technical Reports Server (NTRS)

The characteristics of the feed duct, the wind tunnel, and the experiments run in the convergent-divergent anechoic wind tunnel at Lyon University are described. The wind tunnel was designed to eliminate noise from the entrance of air or from flow interactions with the tunnel walls so that noise caused by the flow-test structure interactions can be studied. The channel contains 1 x 1 x 0.2 m glass and metal foil baffles spaced 0.2 m apart. The flow is forced by a 350 kW fan in the primary circuit, and a 110 kW blower in the secondary circuit. The primary circuit features a factor of four throat reductions, followed by a 1.6 reduction before the test section. Upstream and downstream sensors permit monitoring of the anechoic effectiveness of the channel. Other sensors allow modeling of the flow structures in the tunnel. The tunnel was used to examine turbulent boundary layers in flows up to 140 m/sec, tubulence-excited vibrations in walls, and the effects of laminar and turbulent flows on the appearance and locations of noise sources.

Sunyach, M.; Brunel, B.; Comte-Bellot, G.

1986-01-01

179

Two chamber reaction furnace  

Microsoft Academic Search

A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber.

Blaugher; Richard D

1998-01-01

180

cetinney@mail.utexas.eduTheUniversityofTexasatAustin,CharlesE.Tinney,Ph.D.,JayantSirohi,Ph.D.,(512)471-4147 http://www.ae.utexas.edu/facultysites/tinney/  

E-print Network

Brian Donald Alexis Avram Lauren Cooper The open jet wind tunnel and fully anechoic chamber at the J://www.ae.utexas.edu/facultysites/tinney/ ·! Facility Overview: ­! Anechoic chamber: ·! 18ft-10in(L) x 14ft-10in(W) x 12ft (H) interior dimensions (wedge tip to wedge tip) ·! Fully anechoic chamber with 99% sound absorption above 100Hz. ·! Class-A fire

Tinney, Charles E.

181

Two chamber reaction furnace  

Microsoft Academic Search

A vertical two chamber reaction furnace is described. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the

Blaugher

1998-01-01

182

D0 central tracking chamber performance studies  

SciTech Connect

The performance of the completed DO central tracking chamber was studied using cosmic rays at the State University of New York at Stony Brook. Also studied was a prototype tracking chamber identical in design to the completed DO tracking chamber. The prototype chamber was exposed to a collimated beam of 150 GeV pions at the Fermilab NWA test facility. Results indicate an R{Phi} tracking resolution compatible with the limitations imposed by physical considerations, excellent 2 track resolution, and a high track reconstruction efficiency along with a good rejection power against {gamma} {yields} e {sup +} e{sup {minus}} events.

Pizzuto, D.

1991-12-01

183

meters in CO2 euthanasia chambers. All CO2 euthanasia chambers in both  

E-print Network

meters in CO2 euthanasia chambers. All CO2 euthanasia chambers in both the facilities and be compliant with necessary changes to euthanasia practices by September 1st , 2013. As happens all too often" for acceptable euthanasia methods. In March 2013, OLAW released a notice for the "Implementation of the Updated

Bushman, Frederic

184

Charging apparatus for coke cooling chambers  

SciTech Connect

An apparatus for charging coke chambers is disclosed which effectively reduces and controls gas and dust emissions evolved during the coke charging operation. The charging apparatus includes a gas-tight enclosure which seals the immediate area surrounding the cooling chamber or serially arranged chambers in a cooling plant, a lift transport facility located internally to the enclosure for carrying a coke bucket to and from the respective coke cooling chambers, a crane or elevator for placing and removing the coke bucket from the lift transport facility, and an exhaust device for evacuating the gas and dust emissions from the enclosure. Inert gas feedlines are integrated with the charging operation to maintain an inert gas atmosphere within the enclosure.

Galow, M.; Joseph, H.

1983-07-12

185

Anechoic Sphere Phantoms for Estimating 3-D Resolution of Very High Frequency Ultrasound Scanners  

PubMed Central

Two phantoms have been constructed for assessing the performance of high frequency ultrasound imagers. They also allow for periodic quality assurance tests. The phantoms contain eight blocks of tissue-mimicking material where each block contains a spatially random distribution of suitably small anechoic spheres having a small distribution of diameters. The eight mean sphere diameters are distributed from 0.10 to 1.09 mm. The two phantoms differ primarily in terms of the backscatter coefficient of the background material in which the spheres are suspended. The mean scatterer diameter for one phantom is larger than that for the other phantom resulting in a lesser increase in backscatter coefficient for the second phantom; however, the backscatter curves cross at about 35 MHz. Since spheres have no preferred orientation, all three (spatial) dimensions of resolution contribute to sphere detection on an equal basis; thus, the resolution is termed 3-D. Two high frequency scanners are compared. One employs single-element (fixed focus) transducers, and the other employs variable focus linear arrays. The nominal frequency for the single element transducers were 25 and 55 MHz and for the linear array transducers were 20, 30 and 40 MHz. The depth range for detection of spheres of each size is determined corresponding to determination of 3-D resolution as a function of depth. As expected, the single-element transducers are severely limited in useful imaging depth ranges compared with the linear arrays. Note that these phantoms could also be useful for training technicians in using higher frequency scanners. PMID:20889416

Madsen, Ernest L.; Frank, Gary R.; McCormick, Matthew M.; Deaner, Meagan E.; Stiles, Timothy A.

2013-01-01

186

Two chamber reaction furnace  

DOEpatents

A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

Blaugher, Richard D. (Evergreen, CO)

1998-05-05

187

Two chamber reaction furnace  

DOEpatents

A vertical two chamber reaction furnace is described. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700 C and 800 C) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800 to 950 C to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product. 2 figs.

Blaugher, R.D.

1998-05-05

188

Temperature Studies for ATLAS MDT BOS Chambers  

E-print Network

Data sets with high statistics taken at the cosmic ray facility, equipped with 3 ATLAS BOS MDT chambers, in Garching (Munich) have been used to study temperature and pressure effects on gas gain and drifttime. The deformation of a thermally expanded chamber was reconstructed using the internal RasNik alignment monitoring system and the tracks from cosmic data. For these studies a heating system was designed to increase the temperature of the middle chamber by up to 20 Kelvins over room temperature. For comparison the temperature effects on gas properties have been simulated with Garfield. The maximum drifttime decreased under temperature raise by -2.21 +- 0.08 ns/K, in agreement with the results of pressure variations and the Garfield simulation. The increased temperatures led to a linear increase of the gas gain of about 2.1% 1/K. The chamber deformation has been analyzed with the help of reconstructed tracks. By the comparison of the tracks through the reference chambers with these through the test chamber the thermal expansion has been reconstructed and the result shows agreement with the theoretical expansion coefficient. As the wires are fixed at the end of the chamber, the wire position calculation can not provide a conclusion for the chamber middle. The complete deformation has been identified with the analysis of the monitoring system RasNik, whose measured values have shown a homogeneous expansion of the whole chamber, overlayed by a shift and a rotation of the chamber middle with respect to the outer part of the chamber. The established results of both methods are in agreement. We present as well a model for the position-drifttime correction as function of temperature.

A. Engl; O. Biebel; R. Hertenberger; R. Mameghani; D. Merkl; F. Rauscher; D. Schaile; R. Stroehmer

2009-08-11

189

Vertical two chamber reaction furnace  

Microsoft Academic Search

A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber.

Blaugher; Richard D

1999-01-01

190

BOREAS TGB-1 NSA SF6 Chamber Flux Data  

NASA Technical Reports Server (NTRS)

The BOREAS TGB-1 team made several chamber and tower measurements of trace gases at sites in the BOREAS NSA. This data set contains sulfur hexafluoride (SF6) dark chamber flux measurements at the NSA-OJP and NSA-YJP sites from 16-May through 13-Sep-1994. Gas samples were extracted approximately every 7 days from dark chambers and analyzed at the NSA lab facility. The data are provided in tabular ASCII files.

Crill, Patrick; Varner, Ruth K.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

2000-01-01

191

Drift Velocity Calibration for the CLAS Drift Chamber System  

Microsoft Academic Search

The University of Richmond Physics Department is responsible for projects being developed for the Continuous Electron Beam Accelerator Facility (CEBAF). We have constructed a prototype of the bow section of the Region 3 drift chambers of Hall B, called the nose cone prototype. Cosmic rays travel through the chamber and ionize atoms from its argon\\/ethane gas mixture. The displaced electrons

Stephen L. Levy; Gerard P. Gilfoyle; Mac Mestayer

1996-01-01

192

OUTDOOR SMOG CHAMBER EXPERIMENTS TO TEST PHOTOCHEMICAL MODELS  

EPA Science Inventory

The smog chamber facility of the University of North Carolina was used in a study to provide experimental data for developing and testing kinetic mechanisms of photochemical smog formation. The smog chamber, located outdoors in rural North Carolina, is an A-frame structure covere...

193

16. NBS TOPSIDE CONTROL ROOM, THE NBS HYPERBARIC CHAMBER IS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. NBS TOPSIDE CONTROL ROOM, THE NBS HYPERBARIC CHAMBER IS VERY CLOSE TO THE WATER'S EDGE AND HERE FOR DIVER EMERGENCY SUPPORT. A MEDICAL STAFF IS LOCATED ON THE MARSHALL SPACE FLIGHT CENTER (MSFC) AND SUPPORTS THE NBS PERSONNEL WHEN HYPERBARIC CHAMBER OPERATION IS NECESSARY. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

194

Evaluation of carbon dioxide dissipation within a euthanasia chamber.  

PubMed

CO? euthanasia is used widely for small laboratory animals, such as rodents. A common necessity in many animal research facilities is to euthanize mice in sequential batches. We assessed the effects of several variables on the time it took for CO? to dissipate within a chamber. Using standard euthanasia time, changes in flow rate were compared between a slow 15% fill rate for 7 min, and a slow 15% followed by a rapid 50% filling for a total of 5 min. Additional variables assessed included the effects of opening the lid after the completion of chamber filling, turning the chamber over after completion of filling, and the use and removal of a cage from within the chamber. For all trials, CO? levels in the chambers peaked between 50% and 80%. After the gas was turned off, the concentration of CO? dropped to below 10% COv within 2 min, except when the lid was left on the chamber, where concentration levels remained above 10% after 20 min. CO? dissipation was significantly faster when the chamber was turned upside down after filling. Significant interaction effects occurred among the factors of cage presence within the chamber, flow rate, and chamber position. Only leaving the lid on the chamber had any practical implication for delaying CO? dissipation. We recommend that users allow 2 min for CO? to clear from the chamber before subsequent euthanasia procedures, unless the chamber is manipulated to increase the dissipation rate. PMID:25199098

Djoufack-Momo, Shelly M; Amparan, Ashlee A; Grunden, Beverly; Boivin, Gregory P-

2014-07-01

195

Evaluation of Carbon Dioxide Dissipation within a Euthanasia Chamber  

PubMed Central

CO2 euthanasia is used widely for small laboratory animals, such as rodents. A common necessity in many animal research facilities is to euthanize mice in sequential batches. We assessed the effects of several variables on the time it took for CO2 to dissipate within a chamber. Using standard euthanasia time, changes in flow rate were compared between a slow 15% fill rate for 7 min, and a slow 15% followed by a rapid 50% filling for a total of 5 min. Additional variables assessed included the effects of opening the lid after the completion of chamber filling, turning the chamber over after completion of filling, and the use and removal of a cage from within the chamber. For all trials, CO2 levels in the chambers peaked between 50% and 80%. After the gas was turned off, the concentration of CO2 dropped to below 10% CO2 within 2 min, except when the lid was left on the chamber, where concentration levels remained above 10% after 20 min. CO2 dissipation was significantly faster when the chamber was turned upside down after filling. Significant interaction effects occurred among the factors of cage presence within the chamber, flow rate, and chamber position. Only leaving the lid on the chamber had any practical implication for delaying CO2 dissipation. We recommend that users allow 2 min for CO2 to clear from the chamber before subsequent euthanasia procedures, unless the chamber is manipulated to increase the dissipation rate. PMID:25199098

Djoufack-Momo, Shelly M; Amparan, Ashlee A; Grunden, Beverly; Boivin, Gregory P

2014-01-01

196

The Mobile Chamber  

NASA Technical Reports Server (NTRS)

A document discusses a simulation chamber that represents a shift from the thermal-vacuum chamber stereotype. This innovation, currently in development, combines the capabilities of space simulation chambers, the user-friendliness of modern-day electronics, and the modularity of plug-and-play computing. The Mobile Chamber is a customized test chamber that can be deployed with great ease, and is capable of bringing payloads at temperatures down to 20 K, in high vacuum, and with the desired metrology instruments integrated to the systems control. Flexure plans to lease Mobile Chambers, making them affordable for smaller budgets and available to a larger customer base. A key feature of this design will be an Apple iPad-like user interface that allows someone with minimal training to control the environment inside the chamber, and to simulate the required extreme environments. The feedback of thermal, pressure, and other measurements is delivered in a 3D CAD model of the chamber's payload and support hardware. This GUI will provide the user with a better understanding of the payload than any existing thermal-vacuum system.

Scharfstein, Gregory; Cox, Russell

2012-01-01

197

Static diffusion cloud chambers  

NASA Technical Reports Server (NTRS)

The chamber geometry and optical arrangement are described. The supersaturation range is given and consists of readings taken at five fixed points: 0.25%, 0.5%, 0.75%, 1.0%, and 1.25%. The detection system is described including light source, cameras, and photocell detectors. The temperature control and the calibration of the chamber are discussed.

Ayers, G.

1981-01-01

198

Vertical two chamber reaction furnace  

Microsoft Academic Search

A vertical two chamber reaction furnace is disclosed. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the

Blaugher

1999-01-01

199

Multiple piston expansion chamber engine  

Microsoft Academic Search

The method of operation for the extraction of work from combusted products in two chambers hereafter referred to as working and auxiliary having a means of controlling isolation between the two the chambers is described comprising of isolating the working chamber from the auxiliary chamber when the working chamber piston is at substantially TDC, admitting a charge of pressurized carbureted

1988-01-01

200

Scarf inlet aeroacoustics study/scarf inlet with Boeing ICD  

NASA Technical Reports Server (NTRS)

Photographs shows the Langley 12 inch ADP fan equipped with an inflow control device (ICD) borrowed from the Boeing company. The fan and ICD are inside the anechoic chamber of the ANRF. Photographed in building 1218A, the Anechoic Noise Research Facility.

1999-01-01

201

Scarf inlet aeroacoustics study/scarf inlet with Boeing ICD  

NASA Technical Reports Server (NTRS)

Photographs shows the Langley 12 inch ADP fan equipped with an inflow control device (ICD) borrowed from the Boeing company. The fan and ICD are inside the anechoic chamber of the ANRF. Lorenzo R. Clark is in the photograph. Photographed in building 1218A, the Anechoic Noise Research Facility.

1999-01-01

202

Acoustic-RF Anechoic Chamber Construction and Evaluation Glenwood Garner III, Jonathan Wilkerson, Michael M. Skeen, Daniel F. Patrick, Ryan D. Hodges,  

E-print Network

using the same process. Support for the walls is via an extruded aluminum space frame manufactured by 80 to a design that measures 8 feet in width, 6 feet in height, and 12 feet long. Furthermore, measurements show

203

Acoustic-Levitation Chamber  

NASA Technical Reports Server (NTRS)

Uncontaminated environments for highly-pure material processing provided within completely sealed levitation chamber that suspends particles by acoustic excitation. Technique ideally suited for material processing in low gravity environment of space.

Barmatz, M. B.; Granett, D.; Lee, M. C.

1984-01-01

204

Mercury Chamber Considerations  

E-print Network

Mercury Chamber Considerations V. Graves IDS-NF Target Studies July 2011 #12;2 Managed by UT-Battelle for the U.S. Department of Energy Mercury Chamber Considerations, July 2011 Flow Loop Review · 1 cm dia nozzle, 20 m/s jet requires 1.57 liter/sec mercury flow (94.2 liter/min, 24.9 gpm). · MERIT experiment

McDonald, Kirk

205

Slurry-Mixing Chamber  

NASA Technical Reports Server (NTRS)

Paddles and water jets create uniform, continuous flow. Slurry-mixing chamber on hydrojet-jaw mining machine ensures uniform, continuously flowing slurry of coal particles in water. By mixing coal and water at high speed and keeping resulting slurry in constant motion, chamber prevents slurry from becoming dry semisolid that blocks flow. Also prevents coal particles from settling and caking in bends, corners, and other locations where flow changes in direction or speed.

Lewis, E. V.

1985-01-01

206

Sleeve reaction chamber system  

DOEpatents

A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

Northrup, M. Allen (Berkeley, CA); Beeman, Barton V. (San Mateo, CA); Benett, William J. (Livermore, CA); Hadley, Dean R. (Manteca, CA); Landre, Phoebe (Livermore, CA); Lehew, Stacy L. (Livermore, CA); Krulevitch, Peter A. (Pleasanton, CA)

2009-08-25

207

Solar thermal plasma chamber  

NASA Astrophysics Data System (ADS)

A unique solar thermal chamber has been designed and fabricated to produce the maximum concentration of solar energy and highest temperature possible. Its primary purpose was for solar plasma propulsion experiments and related material specimen testing above 3000 Kelvin. The design not only maximized solar concentration, but also, minimized infrared heat loss. This paper provides the underlining theory and operation of the chamber and initial optical correlation to the actual fabricated hardware. The chamber is placed at the focal point of an existing primary concentrator with a 2.74-meter (9 foot) focal length. A quartz lens focuses a smaller sun image at the inlet hole of the mirrored cavity. The lens focuses two image planes at prescribed positions; the sun at the cavity's entrance hole, and the primary concentrator at the junction plane of two surfaces that form the cavity chamber. The back half is an ellipsoid reflector that produces a 1.27 cm diameter final sun image. The image is 'suspended in space' 7.1cm away from the nearest cavity surface, to minimize thermal and contaminate damage to the mirror surfaces. A hemisphere mirror makes up the front chamber and has its center of curvature at the target image, where rays leaving the target are reflected back upon themselves, minimizing radiation losses.

Bonometti, Joseph; Buchele, Donald R.; Castle, Charles H.; Gregory, Don A.

2001-11-01

208

Automated Electrostatics Environmental Chamber  

NASA Technical Reports Server (NTRS)

The Mars Electrostatics Chamber (MEC) is an environmental chamber designed primarily to create atmospheric conditions like those at the surface of Mars to support experiments on electrostatic effects in the Martian environment. The chamber is equipped with a vacuum system, a cryogenic cooling system, an atmospheric-gas replenishing and analysis system, and a computerized control system that can be programmed by the user and that provides both automation and options for manual control. The control system can be set to maintain steady Mars-like conditions or to impose temperature and pressure variations of a Mars diurnal cycle at any given season and latitude. In addition, the MEC can be used in other areas of research because it can create steady or varying atmospheric conditions anywhere within the wide temperature, pressure, and composition ranges between the extremes of Mars-like and Earth-like conditions.

Calle, Carlos; Lewis, Dean C.; Buchanan, Randy K.; Buchanan, Aubri

2005-01-01

209

Automated soil gas monitoring chamber  

DOEpatents

A chamber for trapping soil gases as they evolve from the soil without disturbance to the soil and to the natural microclimate within the chamber has been invented. The chamber opens between measurements and therefore does not alter the metabolic processes that influence soil gas efflux rates. A multiple chamber system provides for repetitive multi-point sampling, undisturbed metabolic soil processes between sampling, and an essentially airtight sampling chamber operating at ambient pressure.

Edwards, Nelson T.; Riggs, Jeffery S.

2003-07-29

210

Filament wound rocket motor chambers  

NASA Technical Reports Server (NTRS)

The design, analysis, fabrication and testing of a Kevlar-49/HBRF-55A filament wound chamber is reported. The chamber was fabricated and successfully tested to 80% of the design burst pressure. Results of the data reduction and analysis from the hydrotest indicate that the chamber design and fabrication techniques used for the chamber were adequate and the chamber should perform adequately in a static test.

1976-01-01

211

Electrostatic Levitator Vacuum Chamber  

NASA Technical Reports Server (NTRS)

Optical ports ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (beam passes through the window at left), positioning lasers (one port is at center), and lamps to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

1998-01-01

212

Multiple piston expansion chamber engine  

SciTech Connect

The method of operation for the extraction of work from combusted products in two chambers hereafter referred to as working and auxiliary having a means of controlling isolation between the two the chambers is described comprising of isolating the working chamber from the auxiliary chamber when the working chamber piston is at substantially TDC, admitting a charge of pressurized carbureted air into the working chamber as the working chamber piston moves toward BDC, closing a valve admitting the charge after the working chamber piston is past BDC but before it is midway to TDC, compressing the charge in the working chamber, initiating combustion of the charge prior to the working chamber piston passing TDC, expanding the combusted products in the working chamber unit a point in the cycle after combustion is completed and before the working chamber piston is within 60 degrees of BDC, and expansion of the combusted products in the working chamber piston chamber prior to establishing communication between the working and auxiliary chambers shall not exceed four.

Jackson, F.W.

1988-05-03

213

Liquid Wall Chambers  

SciTech Connect

The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

Meier, W R

2011-02-24

214

Flame-Test Chamber  

NASA Technical Reports Server (NTRS)

Experimental chamber provides controlled environment for observation and measurement of flames propagating in expanding plume of flammable air/fuel mixture under atmospheric conditions. Designed to evaluate quenching capability of screen-type flame arresters in atmospheric vents of fuel cargo tanks aboard marine cargo vessels.

Bjorklund, R. A.

1984-01-01

215

Spark Chamber Pulsing System  

Microsoft Academic Search

A spark chamber pulser is described in which several avalanche transistors and a step-up transformer drive directly an air spark gap whose trigger electrode is surrounded by barium titanate dielectric. Output pulses of from 1 to 25 kV with a risetime of 1 nsec and an output impedance of less than 1 ? can be obtained. The total delay from

Louis Lavoie; Sherwood Parker; Charles Rey; Daniel M. Schwartz

1964-01-01

216

Solar thermal plasma chamber  

Microsoft Academic Search

A unique solar thermal chamber has been designed and fabricated to produce the maximum concentration of solar energy and highest temperature possible. Its primary purpose was for solar plasma propulsion experiments and related material specimen testing above 3000 Kelvin. The design not only maximized solar concentration, but also, minimized infrared heat loss. This paper provides the underlining theory and operation

Joseph Bonometti; Donald R. Buchele; Charles H. Castle; Don A. Gregory

2001-01-01

217

Improved wire chamber  

DOEpatents

An improved gas mixture for use with proportional counter devices, such as Geiger-Mueller tubes and drift chambers. The improved gas mixture provides a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor. 2 figs.

Atac, M.

1987-05-12

218

Terminal configured vehicle program: Test facilities guide  

NASA Technical Reports Server (NTRS)

The terminal configured vehicle (TCV) program was established to conduct research and to develop and evaluate aircraft and flight management system technology concepts that will benefit conventional take off and landing operations in the terminal area. Emphasis is placed on the development of operating methods for the highly automated environment anticipated in the future. The program involves analyses, simulation, and flight experiments. Flight experiments are conducted using a modified Boeing 737 airplane equipped with highly flexible display and control equipment and an aft flight deck for research purposes. The experimental systems of the Boeing 737 are described including the flight control computer systems, the navigation/guidance system, the control and command panel, and the electronic display system. The ground based facilities used in the program are described including the visual motion simulator, the fixed base simulator, the verification and validation laboratory, and the radio frequency anechoic facility.

1980-01-01

219

Pressurized ion chamber for low energy radiation monitoring  

Microsoft Academic Search

Ion chambers that can respond to gamma energies as low as 35 keV have been developed for environmental and area monitoring for low energy X-ray background at the rotating anode X-ray generator facility and other accelerators at CAT, Indore. They are expected to measure exposure levels ranging from 10 ?r\\/h to 100 mr\\/h. These chambers have an all-welded aluminium construction

K. R Prasad; V Balagi; P. M Dighe; Mary Alex; R Karpagam

1997-01-01

220

Vacuum Chamber Design of NSLS-II Storage Ring  

SciTech Connect

National Synchrotron Light Source II (NSLS II) will be a 3-GeV, 792-meter circumference, 3rd generation synchrotron radiation facility, with ultra low emittance and extremely high brightness. the storage ring has 30 Double-Bend-Achromatic (DBA) cells. in each cell, there are five magnets and chamber girders, and one straight section for insertion devices or Radio Frequency (RF) cavities or injection. Most vacuum chambers are made from extruded aluminum with two different cross sections: one fitted in the dipole magnets, and the other surrounded by multipole magnets. They discuss the layout of the DBA cells, the detailed design of the cell's vacuum chambers, the mounting of the Beam-Position-Monitor (BPM) buttons, discrete absorbers, lumped pumps and the distributed Non-Evaporable Getter (NEG) strips, and describe the fabrication and testing of these prototype cell chambers. The account also details the development of the chamber bakeout process, the NEG stri's supports, and the RF shielded bellows.

Doom,L.; Ferreira, M.; Hseuh, H. C.; Lincoln, F.; Longo, C.; Ravindranath, V.; Sharma, S.

2008-06-11

221

Using the Nova target chamber for high-yield targets  

SciTech Connect

The existing 2.2-m-radius Nova aluminum target chamber, coated and lined with boron-seeded carbon shields, is proposed for use with 1000-MJ-yield targets in the next laser facility. The laser beam and diagnostic holes in the target chamber are left open and the desired 10/sup -2/ Torr vacuum is maintained both inside and outside the target chamber; a larger target chamber room is the vacuum barrier to the atmosphere. The hole area available is three times that necessary to maintain a maximum fluence below 12 J/cm/sup 2/ on optics placed at a radius of 10 m. Maximum stress in the target chamber wall is 73 MPa, which complies with the intent of the ASME Pressure Vessel Code. However, shock waves passing through the inner carbon shield could cause it to comminute. We propose tests and analyses to ensure that the inner carbon shield survives the environment. 13 refs.

Pitts, J.H.

1987-09-28

222

Research on Characteristics of Field Uniformity in Reverberation Chamber Using Two TX Antennas  

NASA Astrophysics Data System (ADS)

This paper presents a method to improve field uniformity using two TX antennas in a reverberation chamber with less steps of a stirrer. A mode-stirred reverberation chamber (MSRC) is considered as an alternative to the semi-anechoic chamber for an electromagnetic compatibility test because it provides a large test volume, a statistically uniform field, and a high maximum electric field. To improve field uniformity, we introduce two transmitting antennas for excitation in an MSRC, and predict statistical distribution of the complex reflection coefficients (scattering parameters). To prove the validation of our theory and the reliability of measurement results, three kinds of stirrers with different shape and sizes were fabricated and their efficiencies were measured in an MSRC, and then field uniformities have been investigated for 1-3GHz frequency within the maximum number of independent samples that stirrers can provide. The measurement results show that the average received power is about 1.5 times as high as when using one transmitting antenna, and field uniformity is improved. Use of two transmitting antennas in an MSRC is regarded as a useful method to improve field uniformity at less stirrer steps, for radiated immunity tests.

Kim, Jung-Hoon; Jang, Tae-Heon; Lim, Sung-Kuk; Lee, Songjun; Yang, Sung-Il

223

Multi-chamber deposition system  

DOEpatents

A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

Jacobson, Richard L. (Roseville, MN); Jeffrey, Frank R. (Shoreview, MN); Westerberg, Roger K. (Cottage Grove, MN)

1989-10-17

224

Multi-chamber deposition system  

DOEpatents

A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

Jacobson, Richard L. (Roseville, MN); Jeffrey, Frank R. (Shoreview, MN); Westerberg, Roger K. (Cottage Grove, MN)

1989-06-27

225

Three chamber negative ion source  

DOEpatents

A negative ion vessel is divided into an excitation chamber, a negative ionization chamber and an extraction chamber by two magnetic filters. Input means introduces neutral molecules into a first chamber where a first electron discharge means vibrationally excites the molecules which migrate to a second chamber. In the second chamber a second electron discharge means ionizes the molecules, producing negative ions which are extracted into or by a third chamber. A first magnetic filter prevents high energy electrons from entering the negative ionization chamber from the excitation chamber. A second magnetic filter prevents high energy electrons from entering the extraction chamber from the negative ionizing chamber. An extraction grid at the end of the negative ion vessel attracts negative ions into the third chamber and accelerates them. Another grid, located adjacent to the extraction grid, carries a small positive voltage in order to inhibit positive ions from migrating into the extraction chamber and contour the plasma potential. Additional electrons can be suppressed from the output flux using ExB forces provided by magnetic field means and the extractor grid electric potential.

Leung, Ka-Ngo (Hercules, CA); Ehlers, Kenneth W. (Alamo, CA); Hiskes, John R. (Livermore, CA)

1985-01-01

226

Multiwire proportional chamber development  

NASA Technical Reports Server (NTRS)

The development of large area multiwire proportional chambers, to be used as high resolution spatial detectors in cosmic ray experiments is described. A readout system was developed which uses a directly coupled, lumped element delay-line whose characteristics are independent of the MWPC design. A complete analysis of the delay-line and the readout electronic system shows that a spatial resolution of about 0.1 mm can be reached with the MWPC operating in the strictly proportional region. This was confirmed by measurements with a small MWPC and Fe-55 X-rays. A simplified analysis was carried out to estimate the theoretical limit of spatial resolution due to delta-rays, spread of the discharge along the anode wire, and inclined trajectories. To calculate the gas gain of MWPC's of different geometrical configurations a method was developed which is based on the knowledge of the first Townsend coefficient of the chamber gas.

Doolittle, R. F.; Pollvogt, U.; Eskovitz, A. J.

1973-01-01

227

Crystals in magma chambers  

NASA Astrophysics Data System (ADS)

Differentiation processes in igneous systems are one way in which the diversity of igneous rocks is produced. Traditionally, magmatic diversity is considered as variations in the overall chemical composition, such as basalt and rhyolite, but I want to extend this definition to include textural diversity. Such textural variations can be manifested as differences in the amount of crystalline (and immiscible liquid) phases and in the origin and identity of such phases. One important differentiation process is crystal-liquid separation by floatation or decantation, which clearly necessitates crystals in the magma. Hence, it is important to determine if magmas in chambers (sensu lato) have crystals. The following discussion is framed in generalities - many exceptions occur. Diabase (dolerite) dykes are a common, widespread result of regional mafic magmatism. The rims of most diabase dykes have few or no phenocrysts and crystals in the cores are commonly thought to have crystallized in place. Hence, this major mafic magmatic source did not have crystals, although compositional diversity of these dykes is commonly explained by crystal-liquid separation. This can be resolved if crystallisation was on the walls on the magma chamber. Similarly, most flood basalts are low in crystals and separation of those that are present cannot always explain the observed compositional diversity. Crystal-rich flows do occur, for example the 'Giant Plagioclase Basalts' of the Deccan series, but the crystals are thought to form or accumulate in a crystal-rich zone beneath the roof of the chamber - the rest of the chamber probably has few crystals. Some magmas from Hawaii contain significant amounts of olivine crystals, but most of these are deformed and cannot have crystallised in the chamber. In this case the crystals are thought to grow as the magma passes through a decollement zone. They may have grown on the walls or been trapped by filters. Basaltic andesite ignimbrites generally have few crystals, in contrast to lavas from the same volcanoes. Hence, crystallisation must be a high-level process before eruption. Layering in mafic intrusions has many different origins, but some appears to be the result of crystal settling. If such mineralogical layering is present then so must crystals have been present in the magma. However, it is only necessary that crystals are present in local regions, such as along the floor, walls or roof. All this suggests that most mafic or intermediate magmas in chambers do not have substantial quantities of crystals, except at the peripheries. Felsic (sensu lato) rocks present a rather different story: Although there are many examples of low-crystallinity felsic tuffs and lavas, there are also large ignimbrites with high crystal contents, such as the Fish Canyon tuff. Indeed a 'typical' andesite or dacite is loaded with crystals, generally with long and complex histories. The widespread occurrence of megacrysts in felsic plutonic, and some volcanic, rocks also suggests that crystals are present in magma chambers and can exist for extended periods of time. This would suggest that it is possible, and indeed common, for a felsic magma chamber to have crystals throughout. The difficulty here for differentiation is the high viscosity of such magmas.

Higgins, M.

2011-12-01

228

Electrostatic Levitator Vaccum Chamber  

NASA Technical Reports Server (NTRS)

Optical ports ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), positioning lasers (one port is at center), and lamps (such as the deuterium arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

1998-01-01

229

Electrostatic Levitator Vacuum Chambers  

NASA Technical Reports Server (NTRS)

Optical prots ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), poisitioning lasers (one port is at center), and lamps (such as the deuterium arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

1998-01-01

230

Electrostatic Levitator Vacuum Chamber  

NASA Technical Reports Server (NTRS)

Optical prots ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), poisitioning lasers (one port is at center), and lamps (arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

1998-01-01

231

Digital optical spark chambers  

SciTech Connect

The authors have constructed and tested a prototype digital readout system for optical spark chambers using a linear, solid state (CCD) detector array. Position resolution of 0.013 mm (sigma) over a 25 centimeter field of view has been demonstrated. This technique should permit the construction of economical, light weight and low power trajectory hodoscopes for use in cosmic ray instrumentation on balloons and in spacecraft.

Evenson, P.; Tuska, E.

1989-02-01

232

Vertical two chamber reaction furnace  

DOEpatents

A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

Blaugher, Richard D. (Evergreen, CO)

1999-03-16

233

Vertical two chamber reaction furnace  

DOEpatents

A vertical two chamber reaction furnace is disclosed. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700 and 800 C) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800 to 950 C to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product. 2 figs.

Blaugher, R.D.

1999-03-16

234

Vibrating-chamber levitation systems  

NASA Technical Reports Server (NTRS)

Systems are described for the acoustic levitation of objects, which enable the use of a sealed rigid chamber to avoid contamination of the levitated object. The apparatus includes a housing forming a substantially closed chamber, and means for vibrating the entire housing at a frequency that produces an acoustic standing wave pattern within the chamber.

Barmatz, M. B.; Granett, D.; Lee, M. C. (inventors)

1985-01-01

235

Peter Meyer Lab Facilities page Tissue Culture Facility  

E-print Network

are regenerated from the transformed tissue using plant growth hormones. #12;2 Plant Growth Facility Transgenic-mediated gene transfer. Transgenic tissue is selected and propagated in the culture room, and transgenic plants plants are grown in the glasshouse or in controlled environment chambers. In Vivo Imaging Facility

Meyer, Peter

236

National Ignition Facility system design requirements conventional facilities SDR001  

SciTech Connect

This System Design Requirements (SDR) document specifies the functions to be performed and the minimum design requirements for the National Ignition Facility (NIF) site infrastructure and conventional facilities. These consist of the physical site and buildings necessary to house the laser, target chamber, target preparation areas, optics support and ancillary functions.

Hands, J.

1996-04-09

237

Neutron irradiation test on ATLAS MDT chambers  

NASA Astrophysics Data System (ADS)

The Monitored Drift Tubes (MDT) chambers of the ATLAS muon spectrometer are crucial for the identification of high-momentum final-state muons, which represent very promising and robust signatures of physics at the LHC. They will operate in a high rate and high background environment and therefore their performances should not significantly degrade for the whole ATLAS data taking. The maximum expected total flux, mainly consisting of neutrons and photons in the MeV range, is of the order of 5 kHz/cm 2 for the barrel MDTs, while at SLHC, with machine working at higher luminosity, fluxes can be 10 times higher. To test detector robustness, a MDT test chamber was exposed to intensive neutron irradiation at the TAPIRO ENEA-Casaccia Research Center facility.

Branchini, P.; Di Luise, S.; Graziani, E.; Mazzotta, C.; Meoni, E.; Morello, G.; Passeri, A.; Petrucci, F.; Policicchio, A.; Salvatore, D.; Schioppa, M.

2007-04-01

238

Review of wire chamber aging  

SciTech Connect

This paper makes an overview of the wire chamber aging problems as a function of various chamber design parameters. It emphasizes the chemistry point of view and many examples are drawn from the plasma chemistry field as a guidance for a possible effort in the wire chamber field. The paper emphasizes the necessity of variable tuning, the importance of purity of the wire chamber environment, as well as it provides a practical list of presently known recommendations. In addition, several models of the wire chamber aging are qualitatively discussed. The paper is based on a summary talk given at the Wire Chamber Aging Workshop held at LBL, Berkeley on January 16-17, 1986. Presented also at Wire Chamber Conference, Vienna, February 25-28, 1986. 74 refs., 18 figs., 11 tabs.

Va'Vra, J.

1986-02-01

239

Initial Back-to-Back Fission Chamber Testing in ATRC  

SciTech Connect

Development and testing of in-pile, real-time neutron sensors for use in Materials Test Reactor experiments is an ongoing project at Idaho National Laboratory. The Advanced Test Reactor National Scientific User Facility has sponsored a series of projects to evaluate neutron detector options in the Advanced Test Reactor Critical Facility (ATRC). Special hardware was designed and fabricated to enable testing of the detectors in the ATRC. Initial testing of Self-Powered Neutron Detectors and miniature fission chambers produced promising results. Follow-on testing required more experiment hardware to be developed. The follow-on testing used a Back-to-Back fission chamber with the intent to provide calibration data, and a means of measuring spectral indices. As indicated within this document, this is the first time in decades that BTB fission chambers have been used in INL facilities. Results from these fission chamber measurements provide a baseline reference for future measurements with Back-to-Back fission chambers.

Benjamin Chase; Troy Unruh; Joy Rempe

2014-06-01

240

Automated protein crystal growth facility  

NASA Technical Reports Server (NTRS)

A customer for the protein crystal growth facility fills the specially designed chamber with the correct solutions, fills the syringes with their quenching solutions, and submits the data needed for the proper growth of their crystal. To make sure that the chambers and syringes are filled correctly, a NASA representative may assist the customer. The data needed is the approximate growth time, the growth temperature, and the desired crystal size, but this data can be changed anytime from the ground, if needed. The chambers are gathered and placed into numbered slots in special drawers. Then, data is entered into a computer for each of the chambers. Technicians map out when each chamber's growth should be activated so that all of the chambers have enough time to grow. All of this data is up-linked to the space station when the previous growth session is over. Anti-vibrational containers need to be constructed for the high forces encountered during the lift off and the landing of the space shuttle, and though our team has not designed these containers, we do not feel that there is any reason why a suitable one could not be made. When the shuttle reaches the space station, an astronaut removes a drawer of quenched chambers from the growth facility and inserts a drawer of new chambers. All twelve of the drawers can be replaced in this fashion. The optical disks can also be removed this way. The old drawers are stored for the trip back to earth. Once inside the growth facility, a chamber is removed by the robot and placed in one of 144 active sites at a time previously picked by a technician. Growth begins when the chamber is inserted into an active site. Then, the sensing system starts to determine the size of the protein crystal. All during the crystal's growth, the customer can view the crystal and read all of the crystal's data, such as growth rate and crystal size. When the sensing system determines that the crystal has reached the predetermined size, the robot is told to pick up a syringe filled with the correct quenchant solution and inject it into the chamber to stop the crystal growth. The chamber is then removed from the active site and placed into its original storage slot. Another chamber is then placed into the active site and the process is repeated in all of the active sites until all of the chambers have complted their growth. After ninety days (the scheduled time between shuttle visits), the crystal growth is completed, and the old drawers are replaced with new ones. Once the customer extracts the crystals, the chambers are retrieved for future customers.

Donald, Stacey

1994-01-01

241

Overview of the ICF 1000 MJ experiment chamber design  

SciTech Connect

A conceptual design of an experiment chamber for a high gain ICF facility (1000 MJ) is being developed. Performance goals have been established. Several design approaches are being evaluated through computer simulation, engineering analysis, and experimental testing of candidate first wall components. 10 refs., 3 figs.

Slaughter, D.

1988-09-23

242

Overview of the ICF 1000 MJ experiment chamber design  

SciTech Connect

A conceptual design of an experiment chamber for a high gain inertial confinement fusion (ICF) facility (1000 MJ) is being developed. Performance goals have been established. Several design approaches are being evaluated through computer simulations, engineering analysis, and experimental testing of candidate first wall components.

Slaughter, D.

1989-03-01

243

14. VIEW OF VACUUM COATING CHAMBER. THE SYSTEM USED TITANIUM ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. VIEW OF VACUUM COATING CHAMBER. THE SYSTEM USED TITANIUM VAPORS TO DEPOSIT TITANIUM COATING ONTO URANIUM PARTS UNDER A VACUUM. (1/11/83) - Rocky Flats Plant, Non-Nuclear Production Facility, South of Cottonwood Avenue, west of Seventh Avenue & east of Building 460, Golden, Jefferson County, CO

244

13. VIEW OF VACUUM CHAMBER AND WELDING EQUIPMENT IN MODULE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. VIEW OF VACUUM CHAMBER AND WELDING EQUIPMENT IN MODULE E. PARTS WERE WELDED UNDER A VACUUM TO PREVENT CORROSION. (11/6/73) - Rocky Flats Plant, Plutonium Manufacturing Facility, North-central section of Plant, just south of Building 776/777, Golden, Jefferson County, CO

245

Aging tests of full scale CMS muon cathode strip chambers  

SciTech Connect

Two CMS production Cathode Strip Chambers were tested for aging effects in the high radiation environment at the Gamma Irradiation Facility at CERN. The chambers were irradiated over a large area: in total, about 2.1 m{sup 2} or 700 m of wire in each chamber. The 40% Ar+50%CO{sub 2}+10%CF{sub 4} gas mixture was provided by an open-loop gas system for one of the chambers and by closed-loop recirculating gas system for the other. After accumulating 0.3-0.4 C per centimeter of a wire, which is equivalent to operation during about 30-50 years at the peak LHC luminosity, no significant changes in gas gain, chamber efficiency, and wire signal noise were observed for either of the two chambers. The only consistent signs of aging were a small increase in dark current from {approx}2 nA to {approx}10 nA per plane of 600 wires and a decrease of strip-to-strip resistance from 1000 G{Omega} to 10-100 G{Omega}. Disassembly of the chambers revealed deposits on the cathode planes, while the anode wires remained fairly clean.

D. Acosta et al.

2003-10-15

246

A large high vacuum, high pumping speed space simulation chamber for electric propulsion  

NASA Technical Reports Server (NTRS)

Testing high power electric propulsion devices poses unique requirements on space simulation facilities. Very high pumping speeds are required to maintain high vacuum levels while handling large volumes of exhaust products. These pumping speeds are significantly higher than those available in most existing vacuum facilities. There is also a requirement for relatively large vacuum chamber dimensions to minimize facility wall/thruster plume interactions and to accommodate far field plume diagnostic measurements. A 4.57 m (15 ft) diameter by 19.2 m (63 ft) long vacuum chamber at NASA Lewis Research Center is described. The chamber utilizes oil diffusion pumps in combination with cryopanels to achieve high vacuum pumping speeds at high vacuum levels. The facility is computer controlled for all phases of operation from start-up, through testing, to shutdown. The computer control system increases the utilization of the facility and reduces the manpower requirements needed for facility operations.

Grisnik, Stanley P.; Parkes, James E.

1994-01-01

247

The Juelich large Aerosol Chamber  

Microsoft Academic Search

The large Aerosol Chamber is designed for the investigation of nighttime atmospheric chemistry. The Aerosol Chamber is a dark chamber and is operated at ambient temperature and pressure conditions. It is constructed as a double wall system: a fully welded aluminum box (7m x 7m x 5.3m) and an equally sized fully heat sealed Teflon bag hanging from the ceiling.

Th. Mentel; A. Wahner; M. Folkers

2003-01-01

248

40 CFR 160.45 - Test system supply facilities.  

Code of Federal Regulations, 2010 CFR

...shall be provided. As specified in the protocol, these include: (1) Facilities for holding, culturing, and maintaining algae and aquatic plants. (2) Facilities for plant growth, including, but not limited to greenhouses, growth chambers,...

2010-07-01

249

40 CFR 160.45 - Test system supply facilities.  

Code of Federal Regulations, 2012 CFR

...shall be provided. As specified in the protocol, these include: (1) Facilities for holding, culturing, and maintaining algae and aquatic plants. (2) Facilities for plant growth, including, but not limited to greenhouses, growth chambers,...

2012-07-01

250

40 CFR 160.45 - Test system supply facilities.  

Code of Federal Regulations, 2011 CFR

...shall be provided. As specified in the protocol, these include: (1) Facilities for holding, culturing, and maintaining algae and aquatic plants. (2) Facilities for plant growth, including, but not limited to greenhouses, growth chambers,...

2011-07-01

251

40 CFR 160.45 - Test system supply facilities.  

Code of Federal Regulations, 2013 CFR

...shall be provided. As specified in the protocol, these include: (1) Facilities for holding, culturing, and maintaining algae and aquatic plants. (2) Facilities for plant growth, including, but not limited to greenhouses, growth chambers,...

2013-07-01

252

40 CFR 160.45 - Test system supply facilities.  

Code of Federal Regulations, 2014 CFR

...shall be provided. As specified in the protocol, these include: (1) Facilities for holding, culturing, and maintaining algae and aquatic plants. (2) Facilities for plant growth, including, but not limited to greenhouses, growth chambers,...

2014-07-01

253

Environmental calibration chamber operations  

NASA Technical Reports Server (NTRS)

Thermal vacuum capabilities are provided for the development, calibration, and functional operation checks of flight sensors, sources, and laboratory and field instruments. Two systems are available. The first is a 46 cm diameter diffusion pumped vacuum chambler of the bell jar variety. It has an internal thermal shroud, LN2 old trap, two viewing ports, and various electrical and fluid feedthroughs. The other, also an oil diffusion pumped system, consists of a 1.8 m diameter by 2.5 m long stainless steel vacuum tank, associated pumping and control equipment, a liquid nitrogen storage and transfer system and internal IR/visible calibration sources. This is a two story system with the chamber located on one floor and the pumping/cryogenic systems located on the floor below.

Lester, D. L.

1988-01-01

254

Chambers's Book of Days  

NSDL National Science Digital Library

Subtitled A Miscellany of Popular Antiquities in connection with the Calendar, Chambers's Book of Days is essentially a collection of "On this Day" trivia, short pieces, and other interesting tidbits, including history, literature, biography, and "oddities of human life and character." Digitized by the University of Wisconsin-Madison Libraries, this electronic reprint may be browsed in page order or via a calendar navigator. The site offers a fun look into pop-history/ tabloid news of the late nineteenth century. For instance, I discovered that on the day of my birth in 1626 "a cod-fish was brought to Cambridge market, which upon being opened, was found to contain a book in its maw or stomach." An auspicious date to be born indeed.

255

Iran Chamber Society  

NSDL National Science Digital Library

In 2001, the Iran Chamber Society was created in order to provide a non-partisan, non-commercial, comprehensive source of information on Iran. The website's "About Us" section states that their aim is to "create a global awareness about Iranian society and eradicate the misunderstandings and misconceptions about Iranian society, and to play an educational role as well." Visitors will find the website divided up into "Art and Culture", "History", "Society" and "Iran's Guide". The "Exhibitions and Conferences" link on the right side of the homepage leads visitors to a number of exhibitions, including the fascinating "Artistic Murals of Tehran's Metro Stations", which offers a dozen pictures of the beautifully handcrafted murals made of pottery, metal, cement and other materials. The "History" section offers pictures and documents, including some disturbing graphic photos from the Iran-Iraq War in 1980-1988 that appear at the end of the Historic Periods and Events section.

256

Mush Column Magma Chambers  

NASA Astrophysics Data System (ADS)

Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior of the system, coupled with these processes, define the fundamental compositional and dynamic diversity of the Mush Column. In some ways it functions like a complex musical instrument. Entrainment, transport, and sorting of cumulate crystals as a function of repose time and the local flux intensity also contribute to the basic compositional diversity of the system. In the Ferrar dolerite system, about 104 km3 of dolerite is distributed throughout a fir-tree like stack of 4 or 5 extensive 300-750 m thick sills. The lowest sill contains a vast tongue of entrained orthopyroxene (opx) cumulates emplaced with the sill itself. The bulk sill composition varies from 20 pc MgO in the tongue center to 7 pc in the leading tip and margins of the sill, which itself defines the compositional spectrum of the whole complex and is remarkably similar to that exhibited by Hawaii. Relative sorting of large (1-50 mm) opx and small (1-3 mm) plagioclase due to kinetic sieving in the tongue produces pervasive anorthosite stringers. Through local ponding this has culminated in the formation of a small, well-formed layered intrusion consisting of alternating layers of orthopyroxenite and anorthosite. Upwards in the system the sills become progressively depleted in MgO and temporally and spatially contiguous flood basalts are low MgO tholeiites with no sign of opx cumulates. The size, extent, number of sills, and the internal structure of individual sills suggest a rhythm of injection similar to that of volcanic episodes. The continued horizontal stretching of a system of this type would lead to processes as recorded by ophiolites, and the repeated injection into a single reservoir would undoubtedly lead to a massive layered intrusion or to a series of high-level nested plutons.

Marsh, B. D.

2002-12-01

257

BOREAS TGB-1/TGB-3 CH4 Chamber Flux Data over the NSA Fen  

NASA Technical Reports Server (NTRS)

The BOREAS TGB-3 team collected methane (CH4) chamber flux measurements at the NSA fen site during May-September 1994 and June-October 1996. Gas samples were extracted approximately every 7 days from chambers and analyzed at the NSA lab facility. The data are provided in tabular ASCII files.

Bubier, Jill L.; Moore, Tim R.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

2000-01-01

258

Fast ion chambers for SLC  

SciTech Connect

Beam diagnostic ion chambers are used throughout the SLC to perform a variety of tasks including locating beam losses along the beam direction, determining localized losses from individual bunches in a multibunch beam, and detecting scattered particles from beam profile wire scanners where backgrounds are too high to use photomultiplier tubes. Construction and instrumentation of very fast ion chambers with pulse duration of less than 60ns are detailed. Long ion chambers referred to as PLIC (Panofsky`s Long Ion Chamber) are the primary diagnostic used to locate losses in all the SLC transport lines. Accurately locating beam loss with the use of fiducial cables and coaxial switches will be discussed.

McCormick, D.

1993-07-01

259

Neutron Detection via Bubble Chambers  

SciTech Connect

The results of a Pacific Northwest National Laboratory (PNNL) exploratory research project investigating the feasibility of fast neutron detection using a suitably prepared and operated, pressure-cycled bubble chamber are described. The research was conducted along two parallel paths. Experiments with a slow pressure-release Halon chamber at the Enrico Fermi Institute at the University of Chicago showed clear bubble nucleation sensitivity to an AmBe neutron source and insensitivity to the 662 keV gammas from a 137Cs source. Bubble formation was documented via high-speed (1000 frames/sec) photography, and the acoustic signature of bubble formation was detected using a piezo-electric transducer element mounted on the base of the chamber. The chamber’s neutron sensitivity as a function of working fluid temperature was mapped out. The second research path consisted of the design, fabrication, and testing of a fast pressure-release Freon-134a chamber at PNNL. The project concluded with successful demonstrations of the PNNL chamber’s AmBe neutron source sensitivity and 137Cs gamma insensitivity. The source response tests of the PNNL chamber were documented with high-speed photography.

Jordan, David V.; Ely, James H.; Peurrung, Anthony J.; Bond, Leonard J.; Collar, J. I.; Flake, Matthew; Knopf, Michael A.; Pitts, W. K.; Shaver, Mark W.; Sonnenschein, Andrew; Smart, John E.; Todd, Lindsay C.

2005-10-06

260

HATCH CONNECTING TEMPERED AIR CHAMBER AND HOT AIR CHAMBER OF ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HATCH CONNECTING TEMPERED AIR CHAMBER AND HOT AIR CHAMBER OF PLENUM WITH ATTACHED DRAFT REGULATOR. - Hot Springs National Park, Bathhouse Row, Superior Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

261

ECRB REFUGE CHAMBER  

SciTech Connect

The purpose of this calculation is to identify the initial design requirements for refuge stations, including the client requirements, standards, codes, laws, and regulations, general discipline design criteria, and design basis events and hazards. The scope of this document is for the specific task of designing and constructing refuge stations in the Enhanced Characterization Repository Block (ECRB) subsurface openings as necessary personnel safety enhancements to the current construction, maintenance and testing operations. This document is for the construction at the Exploratory Site Facility (ESF). The criteria is not intended to be incorporated into the proposed repository design and does not support Site Recommendation or License Application efforts. This calculation is prepared in accordance with N-3.12Q as a field support calculation and was prepared using the ''Technical Work Plan for Test Facilities Design FY01 Work Activities'' (TWP) (CRWMS M&O 2000b).

J. W. Keifer

2001-12-03

262

Fast-response cloud chamber  

NASA Technical Reports Server (NTRS)

Wall structure keeps chambers at constant, uniform temperature, yet allows them to be cooled rapidly if necessary. Wall structure, used in fast-response cloud chamber, has surface heater and coolant shell separated by foam insulation. It is lightweight and requires relatively little power.

Fogal, G. L.

1977-01-01

263

Multiple piston expansion chamber engine  

Microsoft Academic Search

An internal combustion engine is described wherein combustion, expansion and exhaust functions are performed in a cylinder comprised of an auxiliary piston reciprocating in the cylinder, a sleeve valve reciprocating within the auxiliary piston, a working piston reciprocating within the sleeve valve and leading the auxiliary piston, an auxiliary chamber above the auxiliary piston and a combustion chamber above the

1987-01-01

264

Multiple piston expansion chamber engine  

Microsoft Academic Search

This patent describes a multiple piston expansion chamber in an internal combustion engine wherein combustion, expansion and exhaust functions are performed in a cylinder. This cylinder consists of an auxiliary piston reciprocating in the cylinder, a sleeve valve reciprocating within the auxiliary piston, a working piston reciprocating within the sleeve valve. Leading the auxiliary piston is an auxiliary chamber above

1986-01-01

265

Multiple piston expansion chamber engine  

Microsoft Academic Search

This patent describes an internal combustion engine. This engine consists of a cylinder with an auxiliary piston reciprocating in the cylinder; a working piston reciprocating within the auxiliary piston; an auxiliary chamber above the auxiliary piston; a combustion chamber above the working piston and providing a dwell for the auxiliary piston at TDC starting from when the working piston is

1986-01-01

266

Ion chamber based neutron detectors  

DOEpatents

A neutron detector with monolithically integrated readout circuitry, including: a bonded semiconductor die; an ion chamber formed in the bonded semiconductor die; a first electrode and a second electrode formed in the ion chamber; a neutron absorbing material filling the ion chamber; and the readout circuitry which is electrically coupled to the first and second electrodes. The bonded semiconductor die includes an etched semiconductor substrate bonded to an active semiconductor substrate. The readout circuitry is formed in a portion of the active semiconductor substrate. The ion chamber has a substantially planar first surface on which the first electrode is formed and a substantially planar second surface, parallel to the first surface, on which the second electrode is formed. The distance between the first electrode and the second electrode may be equal to or less than the 50% attenuation length for neutrons in the neutron absorbing material filling the ion chamber.

Derzon, Mark S; Galambos, Paul C; Renzi, Ronald F

2014-12-16

267

Proton beam monitor chamber calibration  

NASA Astrophysics Data System (ADS)

The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences—of the order of 3%—were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth—i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers—rather than cylindrical chambers—for the reference dosimetry of pseudo-monoenergetic proton beams.

Gomà, C.; Lorentini, S.; Meer, D.; Safai, S.

2014-09-01

268

Proton beam monitor chamber calibration.  

PubMed

The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences-of the order of 3%-were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth-i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers-rather than cylindrical chambers-for the reference dosimetry of pseudo-monoenergetic proton beams. PMID:25109620

Gomà, C; Lorentini, S; Meer, D; Safai, S

2014-09-01

269

The Experiment: On 7/11/2006, Frank Ghigo, John Ford, and Carla Beaudet performed an experiment to  

E-print Network

by the GBT. As a preliminary experiment, the camera was tested in the anechoic chamber to gain a rough the bus stop, we are fairly confident that we could have seen the camera in L Band. In anechoic chamber ­ 1 GHz, Anechoic Chamber Testing Figure 10: Kodak DC5000, PF1 Band, Anechoic Chamber Testing #12

Groppi, Christopher

270

AN INTRODUCTION TO WORKING IN THE ELECTROMAGNETIC MICROPHYSICS LABORATORY In the modern age, there are two types of scientists: Theoretical, and experimental. In the world of  

E-print Network

inside an anechoic chamber definitely falls under the category of experimental engineering, and so is intended to illustrate the kinds of concerns which arise from working in the anechoic chamber. Anechoic Chambers The point of an anechoic chamber is to create an environment where I can perform

Zhang, Yan

271

Engineering Test Facilities Having the facilities to develop and test spaceflight hardware  

E-print Network

-in and life tests, as well as the more classic thermal balance and thermal cycling tests associated micro balances. Optical Vacuum Test Facilities LASP has designed and built five vacuum chambersEngineering Test Facilities Having the facilities to develop and test spaceflight hardware onsite

Mojzsis, Stephen J.

272

Multiple piston expansion chamber engine  

SciTech Connect

This patent describes a multiple piston expansion chamber in an internal combustion engine wherein combustion, expansion and exhaust functions are performed in a cylinder. This cylinder consists of an auxiliary piston reciprocating in the cylinder, a sleeve valve reciprocating within the auxiliary piston, a working piston reciprocating within the sleeve valve. Leading the auxiliary piston is an auxiliary chamber above the auxiliary piston and a combustion chamber above the working piston. The sleeve valve controls communication of the auxiliary chamber with the combustion chamber to prevent communication of combusted products from the chamber above the working piston to the chamber above the auxiliary piston from when the working piston is at about TDC until a subsequent expansion stroke of the working piston is underway to a point about midway to BDC. When the auxiliary piston is at about TDC at this same instant when the working piston is at the point and the communication then is commenced. In order to permit communication only during the expansion stroke from continuing past the point and a following exhaust stroke of the working piston so as to utilize energy of expansion from the auxiliary piston as it expands until the working piston has passed through BDC and returns to about TDC during the exhaust stroke of the working piston. The controlling means comprises a circular sealing surface on an upward viewing surface of the sleeve valve adjacent to the working piston to prevent communication of the respective chambers. Also provided in the chambers is a dwell of the sleeve valve at its TDC between when the respective pistons each reach their TDC.

Jackson, F.W.

1986-04-08

273

A comparison of the acoustic and aerodynamic measurements of a model rotor tested in two anechoic wind tunnels  

NASA Technical Reports Server (NTRS)

Two aeroacoustic facilities - the CEPRA 19 in France and the DNW in the Netherlands - are compared. The two facilities have unique acoustic characteristics that make them appropriate for acoustic testing of model-scale helicopter rotors. An identical pressure-instrumented model-scale rotor was tested in each facility and acoustic test results are compared with full-scale-rotor test results. Blade surface pressures measured in both tunnels were used to correlated nominal rotor operating conditions in each tunnel, and also used to assess the steadiness of the rotor in each tunnel's flow. In-the-flow rotor acoustic signatures at moderate forward speeds (35-50 m/sec) are presented for each facility and discussed in relation to the differences in tunnel geometries and aeroacoustic characteristics. Both reports are presented in appendices to this paper.

Boxwell, D. A.; Schmitz, F. H.; Splettstoesser, W. R.; Schultz, K. J.; Lewy, S.

1986-01-01

274

A comparison of the acoustic and aerodynamic measurements of a model rotor tested in two anechoic wind tunnels  

NASA Technical Reports Server (NTRS)

Two aeroacoustic facilities--the CEPRA 19 in France and the DNW in the Netherlands--are compared. The two facilities have unique acoustic characteristics that make them appropriate for acoustic testing of model-scale helicopter rotors. An identical pressure-instrumented model-scale rotor was tested in each facility and acoustic test results are compared with full-scale-rotor test results. Blade surface pressures measured in both tunnels were used to correlated nominal rotor operating conditions in each tunnel, and also used to assess the steadiness of the rotor in each tunnel's flow. In-the-flow rotor acoustic signatures at moderate forward speeds (35-50 m/sec) are presented for each facility and discussed in relation to the differences in tunnel geometries and aeroacoustic characteristics. Both reports are presented in appendices to this paper. ;.);

Boxwell, D. A.; Schmitz, F. H.; Splettstoesser, W. R.; Schultz, K. J.; Lewy, S.; Caplot, M.

1986-01-01

275

Electromagnetic propulsion test facility  

NASA Technical Reports Server (NTRS)

A test facility for the exploration of electromagnetic propulsion concept is described. The facility is designed to accommodate electromagnetic rail accelerators of various lengths (1 to 10 meters) and to provide accelerating energies of up to 240 kiloJoules. This accelerating energy is supplied as a current pulse of hundreds of kiloAmps lasting as long as 1 millisecond. The design, installation, and operating characteristics of the pulsed energy system are discussed. The test chamber and its operation at pressures down to 1300 Pascals (10 mm of mercury) are described. Some aspects of safety (interlocking, personnel protection, and operating procedures) are included.

Gooder, S. T.

1984-01-01

276

Ames Hybrid Combustion Facility  

NASA Technical Reports Server (NTRS)

The report summarizes the design, fabrication, safety features, environmental impact, and operation of the Ames Hybrid-Fuel Combustion Facility (HCF). The facility is used in conducting research into the scalability and combustion processes of advanced paraffin-based hybrid fuels for the purpose of assessing their applicability to practical rocket systems. The facility was designed to deliver gaseous oxygen at rates between 0.5 and 16.0 kg/sec to a combustion chamber operating at pressures ranging from 300 to 900. The required run times were of the order of 10 to 20 sec. The facility proved to be robust and reliable and has been used to generate a database of regression-rate measurements of paraffin at oxygen mass flux levels comparable to those of moderate-sized hybrid rocket motors.

Zilliac, Greg; Karabeyoglu, Mustafa A.; Cantwell, Brian; Hunt, Rusty; DeZilwa, Shane; Shoffstall, Mike; Soderman, Paul T.; Bencze, Daniel P. (Technical Monitor)

2003-01-01

277

Ultraviolet laser calibration of drift chambers  

E-print Network

We demonstrate the use of a focused ultraviolet laser as a track calibration source in drift chambers, and specifically in a small time projection chamber (TPC). Drift chambers such as TPCs reconstruct the trajectories of ...

Elliott, Grant (Grant Andrew)

2006-01-01

278

Cyclically controlled welding purge chamber  

NASA Technical Reports Server (NTRS)

An arrangement for butt-welding cylindrical sections of large, thin-wall tanks includes a rotatable mandrel with side-by-side sets of radial position adjusters. Each set of adjusters bears on one of the tank sections adjacent the seam, to prevent the sections from sagging out-of-round. The mandrel rotates relative to the welder, so that a continuous seam is formed. A purge chamber is fixed in position behind the seam at the weld head, and is flushed with inert gas. The purge chamber includes a two-sided structure which is contiguous with the cylindrical sections and a circumferential vane to form an open-ended tube-like structure, through which the radial position adjusters pass as the mandrel and cylindrical workpiece sections rotate. The tube-like structure is formed into a chamber by a plurality of movable gates which are controlled to maintain a seal while allowing adjusters to progress through the purge chamber.

Gallagher, Robert L. (Inventor)

1996-01-01

279

21 CFR 866.2120 - Anaerobic chamber.  

Code of Federal Regulations, 2014 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a...

2014-04-01

280

21 CFR 866.2120 - Anaerobic chamber.  

Code of Federal Regulations, 2011 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a...

2011-04-01

281

21 CFR 866.2120 - Anaerobic chamber.  

Code of Federal Regulations, 2012 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a...

2012-04-01

282

21 CFR 866.2120 - Anaerobic chamber.  

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a...

2013-04-01

283

Light diffusing fiber optic chamber  

DOEpatents

A light diffusion system for transmitting light to a target area. The light is transmitted in a direction from a proximal end to a distal end by an optical fiber. A diffusing chamber is operatively connected to the optical fiber for transmitting the light from the proximal end to the distal end and transmitting said light to said target area. A plug is operatively connected to the diffusing chamber for increasing the light that is transmitted to the target area.

Maitland, Duncan J. (Lafayette, CA)

2002-01-01

284

Spectra, composition, and interactions of nuclei with magnet interaction chambers  

NASA Technical Reports Server (NTRS)

Emulsion chambers will be flown in the Astromag Facility to measure the cosmic ray composition and spectra to 10 exp 15 eV total energy and to definitively study the characteristics of nucleus-nucleus interactions above 10 exp 12 eV/n. Two configurations of emulsion chambers will be flown in the SCIN/MAGIC experiment. One chamber has an emulsion target and a calorimeter similar to those recently flown on balloons for composition and spectra measurements. The other has an identical calorimeter and a low-density target section optimized for performing rigidity measurements on charged particles produced in interactions. The transverse momenta of charged and neutral mesons, direct hadronic pairs from resonance decays and interference effects, and possible charge clustering in high-density states of matter will be studied.

Parneil, T. A.; Derrickson, J. H.; Fountain, W. F.; Roberts, F. E.; Tabuki, T.; Watts, J. W.; Burnett, T. H.; Cherry, M. C.; Dake, S.; Fuki, M.

1990-01-01

285

Multiple piston expansion chamber engine  

SciTech Connect

An internal combustion engine is described wherein combustion, expansion and exhaust functions are performed in a cylinder comprised of an auxiliary piston reciprocating in the cylinder, a sleeve valve reciprocating within the auxiliary piston, a working piston reciprocating within the sleeve valve and leading the auxiliary piston, an auxiliary chamber above the auxiliary piston and a combustion chamber above the working piston. The sleeve valve controlling communication of the auxiliary chamber with the combustion chamber to prevent communication of combusted products from the chamber above the working piston to the chamber above the auxiliary piston from when the working piston is at about TDC until a subsequent expansion stroke of the working piston is underway and at a point between 30 and 160 degrees past TDC and with the auxiliary piston being at about TDC at this same instant when the working piston is at the point and the communication then is commenced. To permit communication only during the expansion stroke continuing past the point and a following exhaust stroke of the working piston so as to utilize energy of expansion from the auxiliary piston as it expands until the working piston has passed through BDC and returns to about TDC during the exhaust stroke of the working piston.

Jackson, F.W.

1987-12-29

286

Multiple piston expansion chamber engine  

SciTech Connect

This patent describes an internal combustion engine. This engine consists of a cylinder with an auxiliary piston reciprocating in the cylinder; a working piston reciprocating within the auxiliary piston; an auxiliary chamber above the auxiliary piston; a combustion chamber above the working piston and providing a dwell for the auxiliary piston at TDC starting from when the working piston is between 40 degrees before to about TDC and on passing TDC entering an expansion stroke. The auxiliary piston remains at TDC until the working piston expansion stroke is underway and at a point where the working piston is between 20 and 160 degrees past TDC during the expansion stroke at which point the auxiliary piston leaves TDC and moves toward BDC. A controller communicating with the combustion chamber and the auxiliary chamber to prevent communication of combusted products from the combustion chamber above the working piston to the chamber above the auxiliary piston while the auxiliary piston is at TDC. The piston at TDC permits communication only during the working piston expansion stroke continuing past the point between 20 and 160 degrees past TDC, and a following exhaust stroke of the working piston so as to utilize energy of expansion from the auxiliary piston as it expands until the working piston has passed through BDC and returns to about TDC during the exhaust stroke of the working piston.

Jackson, F.W.

1986-02-18

287

Neutron facility for radiobiological studies  

NASA Astrophysics Data System (ADS)

A neutron facility suitable for radiobiological applications is described. The small chamber can house, either, solid targets or a gas target. Using this facility, absorbed doses ranging up to 7.2 Gy were delivered to Drosophila melanogaster larvae in order to study induced somatic mutation and mitiotic recombination. Some preliminary results concerning these effects, related to a mean neutron energy of 2.15 MeV provided by a d + Be source, are presented.

Policroniades, Rafael; Varela, A.; Guzman, J.; Graaf, U.

1997-02-01

288

RADIATION ENVIRONMENT OF GROWTH CHAMBERS  

EPA Science Inventory

Radiation measurements with different types of meters in several controlled environment facilities have been compiled to demonstrate the problems associated with insuring uniform radiation levels in separate facilities. Data are provided for a quantum meter, three photometers, a ...

289

White Sands solar test facility  

Microsoft Academic Search

The White Sands solar test facility includes a heliostat, attenuator, concentrator and test and control chamber. A total of 356 flat-plate mirrors mounted on a steel frame 1.2 by 11 m comprises the heliostat, which moves in azimuth + or - 60 deg and from zero to 90 deg in elevation. The concentrator is composed of 180 spherical mirrors mounted

R. A. Hays

1978-01-01

290

Evaluation of Impinging Stream Vortex Chamber Concepts for Liquid Rocket Engine Applications  

NASA Technical Reports Server (NTRS)

To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for liquid rocket engine applications. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concepts not only offer system simplicity, but also enhance the combustion performance. Test results have shown that chamber performance is markedly high even at a low chamber length-to-diameter ratio (LD). This incentive can be translated to a convenience in the thrust chamber packaging. Variations of the vortex chamber concepts have been introduced in the past few decades. These investigations include an ongoing work at Orbital Technologies Corporation (ORBITEC). By injecting the oxidizer tangentially at the chamber convergence and fuel axially at the chamber head end, Knuth et al. were able to keep the wall relatively cold. A recent investigation of the low L/D vortex chamber concept for gel propellants was conducted by Michaels. He used both triplet (two oxidizer orifices and one fuel orifice) and unlike impinging schemes to inject propellants tangentially along the chamber wall. Michaels called the subject injection scheme an Impinging Stream Vortex Chamber (ISVC). His preliminary tests showed that high performance, with an Isp efficiency of 9295, can be obtained. MSFC and the U. S. Army are jointly investigating an application of the ISVC concept for the cryogenic oxygen/hydrocarbon propellant system. This vortex chamber concept is currently tested with gel propellants at AMCOM at Redstone Arsenal, Alabama. A version of this concept for the liquid oxygen (LOX) hydrocarbon fuel (RP-1) system has been derived from the one for the gel propellant. An unlike impinging injector was employed to deliver the propellants to the chamber. MSFC is also conducting an alternative injection scheme, called the chasing injector, associated with this vortex chamber concept. In this injection technique, both propellant jets and their impingement point are in the same chamber cross-sectional plane. Long duration tests (approximately up to 15 seconds) will be conducted on the ISVC to study the thermal effects. This paper will report the progress of the subject efforts at NASA Marshall Space Flight Center. Thrust chamber performance and thermal wall compatibility will be evaluated. The chamber pressures, wall temperatures, and thrust will be measured as appropriate. The test data will be used to validate CFD models, which, in turn, will be used to design the optimum vortex chambers. Measurements in the previous tests showed that the chamber pressures vary significantly with radius. This is due to the existence of the vortices in the chamber flow field. Hence, the combustion efficiency may not be easily determined from chamber pressure. For this project, measured thrust data will be collected. The performance comparison will be in terms of specific impulse efficiencies. In addition to the thrust measurements, several pressure and temperature readings at various locations on the chamber head faceplate and the chamber wall will be made. The first injector and chamber were designed and fabricated based on the available data and experience gained during gel propellant system tests by the U.S. Army. The alternate injector for the ISVC was also fabricated. Hot-fire tests of the vortex chamber are about to start and are expected to complete in February of 2003 at the TS115 facility of MSFC.

Trinh, Huu P.; Bullard, Brad; Kopicz, Charles; Michaels, Scott

2002-01-01

291

ISIS Facility: Facility Design Challenges  

E-print Network

driven · Safety ­ People ­ Environment Facility Design Goals #12;Facility Design Challenges · TechnicalISIS Facility: Facility Design Challenges Matt Fletcher Head, Design Division ISIS Department development #12;Additional Liquid Metal Target Challenges Design and Operational Features of a Mercury Target

McDonald, Kirk

292

Iridium-Coated Rhenium Combustion Chamber  

NASA Technical Reports Server (NTRS)

Iridium-coated rhenium combustion chamber withstands operating temperatures up to 2,200 degrees C. Chamber designed to replace older silicide-coated combustion chamber in small rocket engine. Modified versions of newer chamber could be designed for use on Earth in gas turbines, ramjets, and scramjets.

Schneider, Steven J.; Tuffias, Robert H.; Rosenberg, Sanders D.

1994-01-01

293

A multipurpose facility for metallographic studies  

Microsoft Academic Search

The paper outlines the design concept and capabilities of a computer-controlled multipurpose facility for simultaneous investigation of the microstructure, electrical resistivity, thermal expansion coefficient, melting point, and thermal analysis of refractory and rare metals on just one specimen of small size. The facility consists of several units, including a vacuum unit, working chambers, heating unit, recording of parameters, and a

E. M. Savitskii; I. V. Burov; K. P. Bondarenko; L. M. Telnova; V. I. Vybornov; N. A. Tomilin; M. E. Naidich; O. V. Diufel

1975-01-01

294

Plasma chemistry in wire chambers  

SciTech Connect

The phenomenology of wire chamber aging is discussed and fundamentals of proportional counters are presented. Free-radical polymerization and plasma polymerization are discussed. The chemistry of wire aging is reviewed. Similarities between wire chamber plasma (>1 atm dc-discharge) and low-pressure rf-discharge plasmas, which have been more widely studied, are suggested. Construction and use of a system to allow study of the plasma reactions occurring in wire chambers is reported. A proportional tube irradiated by an {sup 55}Fe source is used as a model wire chamber. Condensable species in the proportional tube effluent are concentrated in a cryotrap and analyzed by gas chromatography/mass spectrometry. Several different wire chamber gases (methane, argon/methane, ethane, argon/ethane, propane, argon/isobutane) are tested and their reaction products qualitatively identified. For all gases tested except those containing methane, use of hygroscopic filters to remove trace water and oxygen contaminants from the gas resulted in an increase in the average molecular weight of the products, consistent with results from low-pressure rf-discharge plasmas. It is suggested that because water and oxygen inhibit polymer growth in the gas phase that they may also reduce polymer deposition in proportional tubes and therefore retard wire aging processes. Mechanistic implications of the plasma reactions of hydrocarbons with oxygen are suggested. Unresolved issues in this work and proposals for further study are discussed.

Wise, J.

1990-05-01

295

Emulsion Chamber Technology Experiment (ECT)  

NASA Technical Reports Server (NTRS)

The experimental objective of Emulsion Chamber Technology (ECT) was to develop space-borne emulsion chamber technology so that cosmic rays and nuclear interactions may subsequently be studied at extremely high energies with long exposures in space. A small emulsion chamber was built and flown on flight STS-62 of the Columbia in March 1994. Analysis of the several hundred layers of radiation-sensitive material has shown excellent post-flight condition and suitability for cosmic ray physics analysis at much longer exposures. Temperature control of the stack was 20 +/-1 C throughout the active control period and no significant deviations of temperature or pressure in the chamber were observed over the entire mission operations period. The unfortunate flight attitude of the orbiter (almost 90% Earth viewing) prevented any significant number of heavy particles (Z greater than or equal to 10) reaching the stack and the inverted flow of shower particles in the calorimeter has not allowed evaluation of absolute primary cosmic ray-detection efficiency nor of the practical time limits of useful exposure of these calorimeters in space to the level of detail originally planned. Nevertheless, analysis of the observed backgrounds and quality of the processed photographic and plastic materials after the flight show that productive exposures of emulsion chambers are feasible in low orbit for periods of up to one year or longer. The engineering approaches taken in the ECT program were proven effective and no major environmental obstacles to prolonged flight are evident.

Gregory, John C.; Takahashi, Yoshiyuki

1996-01-01

296

Annular-Cross-Section CFE Chamber  

NASA Technical Reports Server (NTRS)

Proposed continuous-flow-electrophoresis (CFE) chamber of annular cross section offers advantages over conventional CFE chamber, and wedge-cross-section chamber described in "Increasing Sensitivity in Continuous-Flow Electrophoresis" (MFS-26176). In comparison with wedge-shaped chamber, chamber of annular cross section virtually eliminates such wall effects as electro-osmosis and transverse gradients of velocity. Sensitivity enhanced by incorporating gradient maker and radial (collateral) flow.

Sharnez, Rizwan; Sammons, David W.

1994-01-01

297

Hydrostatic Hyperbaric Chamber Ventilation System  

NASA Technical Reports Server (NTRS)

The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications, including the treatment of medical conditions. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy available in the developing world for the treatment of a variety of medical conditions. Specifically, hyperbaric oxygen therapy is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. Hyperbaric oxygen therapy is simply too expensive and too dangerous to implement in the developing world using standard equipment. The hydrostatic hyperbaric chamber technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system that will provide controlled pressurization of the system, and provide adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the patient and operating personnel, and physiological considerations. The simple schematic, comprised of easily acquired commercial hardware, supports sustainability.

Sargusingh, Miriam M.

2011-01-01

298

Transferring calibration coefficients from ionisation chambers used for diagnostic radiology to transmission chambers.  

PubMed

In this work, the response of a double volume transmission ionisation chamber, developed at the Instituto de Pesquisas Energéticas e Nucleares, was compared to that of a commercial transmission chamber. Both ionisation chambers were tested in different X-ray beam qualities using secondary standard ionisation chambers as reference dosimeters. These standard ionisation chambers were a parallel-plate and a cylindrical ionisation chambers, used for diagnostic radiology and mammography beam qualities, respectively. The response of both transmission chambers was compared to that of the secondary standard chambers to obtain coefficients of equivalence. These coefficients allow the transmission chambers to be used as reference equipment. PMID:22269337

Yoshizumi, Maíra T; Caldas, Linda V E

2012-07-01

299

Blogs are Echo Chambers: Blogs are Echo Chambers  

Microsoft Academic Search

In the last decade, blogs have exploded in number, popularity and scope. However, many commentators and researchers speculate that blogs isolate readers in echo chambers, cutting them off from dissenting opin- ions. Our empirical paper tests this hypothesis. Using a hand-coded sample of over 1,000 comments from 33 of the world's top blogs, we find that agreement out- numbers disagreement

Eric Gilbert; Tony Bergstrom; Karrie Karahalios

2009-01-01

300

CHAMBERS FERRY ROADLESS AREA, TEXAS.  

USGS Publications Warehouse

A geologic and geochemical investigation of the Chambers Ferry Roadless Area, Texas was conducted. The area has probable mineral-resource potential for oil and gas and for lignite. No metallic or additional energy resources were identified in the investigation. Detailed analyses of well logs from the vicinity of the Chambers Ferry Roadless Area, in conjunction with seismic data, are necessary to determine if the subsurface stratigraphy and structure are favorable for the accumulation of oil and gas. A shallow drilling program involving coring on a close-space grid is necessary for determination of the rank and continuity of seams of lignitic sediments in the area.

Houser, B.B.; Ryan, George S.

1984-01-01

301

Liquid deuteromethane pulse ionization chamber  

NASA Astrophysics Data System (ADS)

The serviceability of a pulse ionization chamber filled with liquid deuteromethane (LCD 4) is confirmed experimentally. Deuteromethane with a level of electronegative impurities of 3 × 10 -9 equiv. O 2 has been obtained using Ni/SiO 2 adsorbent. It is shown that for electric fields up to 3kV/cm, the electronic properties of LCD 4 are close to those of LCH 4. The ionization chamber shows an energy resolution of 14%(FWHM) when detecting 1.2 MeV ?-rays.

Barabash, A. S.; Belogurov, S. G.; Kornoukhov, V. N.; Kuzichev, V. F.; Stekhanov, V. N.

1999-02-01

302

Uncertainty analysis of the AEDC 7V chamber  

NASA Astrophysics Data System (ADS)

For over 30 years, the Space Systems Test Facility and space chambers at the Arnold Engineering Development Center (AEDC) have been used to perform space sensor characterization, calibration, and mission simulation testing of space-based, interceptor, and airborne sensors. In partnership with the Missile Defense Agency (MDA), capability upgrades are continuously pursued to keep pace with evolving sensor technologies. Upgrades to sensor test facilities require rigorous facility characterization and calibration activities that are part of AEDC's annual activities to comply with Major Range Test Facility Base processes to ensure quality metrology and test data. This paper discusses the ongoing effort to characterize and quantify Aerospace Chamber 7V measurement uncertainties. The 7V Chamber is a state-of-the-art cryogenic/vacuum facility providing calibration and high-fidelity mission simulation for infrared seekers and sensors against a low-infrared background. One of its key features is the high fidelity of the radiometric calibration process. Calibration of the radiometric sources used is traceable to the National Institute of Standards and Technology and provides relative uncertainties on the order of two to three percent, based on measurement data acquired during many test periods. Three types of sources of measurement error and top-level uncertainties have been analyzed; these include radiometric calibration, target position, and spectral output. The approach used and presented is to quantify uncertainties of each component in the optical system and then build uncertainty diagrams and easily updated databases to detail the uncertainty for each optical system. The formalism, equations, and corresponding analyses are provided to help describe how the specific quantities are derived and currently used. This paper presents the uncertainty methodology used and current results.

Crider, Dustin; Lowry, Heard; Nicholson, Randy; Mead, Kimberly

2005-05-01

303

Space simulation facilities providing a stable thermal vacuum facility  

NASA Technical Reports Server (NTRS)

CBI has recently constructed the Intermediate Thermal Vacuum Facility. Built as a corporate facility, the installation will first be used on the Boost Surveillance and Tracking System (BSTS) program. It will also be used to develop and test other sensor systems. The horizontal chamber has a horseshoe shaped cross section and is supported on pneumatic isolators for vibration isolation. The chamber structure was designed to meet stability and stiffness requirements. The design process included measurement of the ambient ground vibrations, analysis of various foundation test article support configurations, design and analysis of the chamber shell and modal testing of the chamber shell. A detailed 3-D finite element analysis was made in the design stage to predict the lowest three natural frequencies and mode shapes and to identify local vibrating components. The design process is described and the results are compared of the finite element analysis to the results of the field modal testing and analysis for the 3 lowest natural frequencies and mode shapes. Concepts are also presented for stiffening large steel structures along with methods to improve test article stability in large space simulation facilities.

Tellalian, Martin L.

1990-01-01

304

Drift and proportional tracking chambers  

SciTech Connect

Many techniques have been exploited in constructing tracking chambers, particle detectors which measure the trajectories and momenta of charged particles. The particular features of high-energy interactions - charged particle multiplicities, angular correlations and complex vertex topologies, to name a few - and the experimental environment of the accelerator - event rates, background rates, and so on - accent the importance of certain detector characteristics. In high energy e/sup +/e/sup -/, anti pp and pp interactions the final states are dominated by closely collimated jets of high multiplicity, requiring good track-pair resolution in the tracking chamber. High energy particles deflect very little in limited magnetic field volumes, necessitating good spatial resolution for accurate momentum measurements. The colliding beam technique generally requires a device easily adapted to full solid-angle coverage, and the high event rates expected in some of these machines put a premium on good time resolution. Finally, the production and subsequent decays of the tau, charmed and beautiful mesons will provide multiple vertex topologies. To reconstruct these vertices reliably will require considerable improvements in spatial resolution and track-pair resolution. This lecture considers the proportional counter and its descendant, the drift chamber, as tracking chambers. Its goal is to review the physics of this device in order to understand its performance limitations and promises.

Jaros, J.A.

1980-11-01

305

The STAR Resistive Plate Chambers  

E-print Network

Plate Chamber Note 1: internal glass plates electrically floating - take and keep correct voltage, Clermont-Ferrand 2 Float Glass: Bakelite: Has a stable resistivity (hopping conductivity) =10.V. Pick-up electrode Mylar Carbon layer glass glass glass glass glass glass Mylar Carbon layer Pick

Llope, William J.

306

Spark Chamber Track Measuring System  

Microsoft Academic Search

A system is described for the projection, digitizing, and recording of photographed spark chamber tracks. A Slo-Syn-driven projector automatically frames the film and projects the tracks on a screen mounted in a precision commercial plotting board. A reticle projector, mounted on the plotting board pen holder, is manually positioned by means of the plotting board drive tapes which also drive

James A. DeShong

1962-01-01

307

Spark Chamber Track Measuring System  

Microsoft Academic Search

S>A system is described for the projection, digitizing, and recording of ; photographed spark chamber tracks. A SloSyn-driven projector automatically ; frames the film and projects the traeks on a screen mounted in a precision ; commercial plotting board. A reticle projector, mounted on the plotting board ; pen holder, is manually positioned by means of the plotting board drive

James A. Deshong Jr.; J. A. Jr

1962-01-01

308

Chamber Singers Winter, 12 Schedule  

E-print Network

:00 Band Concert in Main F.25 6:00 call, Madrigal Dinner Chamber Singers is a performing group--attendance at the concert is required to receive a passing grade. Additional Information · The call for each concert the concert.No exceptions.Period. · Attendance at the Dress Rehearsal is required.Anyone missing the dress

309

Chamber Clearing First Principles Modeling  

SciTech Connect

LIFE fusion is designed to generate 37.5 MJ of energy per shot, at 13.3 Hz, for a total average fusion power of 500 MW. The energy from each shot is partitioned among neutrons ({approx}78%), x-rays ({approx}12%), and ions ({approx}10%). First wall heating is dominated by x-rays and debris because the neutron mean free path is much longer than the wall thickness. Ion implantation in the first wall also causes damage such as blistering if not prevented. To moderate the peak-pulse heating, the LIFE fusion chamber is filled with a gas (such as xenon) to reduce the peak-pulse heat load. The debris ions and majority of the x-rays stop in the gas, which re-radiates this energy over a longer timescale (allowing time for heat conduction to cool the first wall sufficiently to avoid damage). After a shot, because of the x-ray and ion deposition, the chamber fill gas is hot and turbulent and contains debris ions. The debris needs to be removed. The ions increase the gas density, may cluster or form aerosols, and can interfere with the propagation of the laser beams to the target for the next shot. Moreover, the tritium and high-Z hohlraum debris needs to be recovered for reuse. Additionally, the cryogenic target needs to survive transport through the gas mixture to the chamber center. Hence, it will be necessary to clear the chamber of the hot contaminated gas mixture and refill it with a cool, clean gas between shots. The refilling process may create density gradients that could interfere with beam propagation, so the fluid dynamics must be studied carefully. This paper describes an analytic modeling effort to study the clearing and refilling process for the LIFE fusion chamber. The models used here are derived from first principles and balances of mass and energy, with the intent of providing a first estimate of clearing rates, clearing times, fractional removal of ions, equilibrated chamber temperatures, and equilibrated ion concentrations for the chamber. These can be used to scope the overall problem and provide input to further studies using fluid dynamics and other more sophisticated tools.

Loosmore, G

2009-06-09

310

Ionisation Chambers and Secondary Emission Monitors at the PROSCAN Beam Lines  

SciTech Connect

PROSCAN, the dedicated new medical facility at PSI using proton beams for the treatment of deep seated tumours and eye melanoma, is now in the commissioning phase. Air filled ionisation chambers in several configurations are used as current monitors, profile monitors, halo, position and loss monitors at the PROSCAN beam lines. Similar monitors based on secondary emission are used for profile and current measurements in the regime where saturation deteriorates the accuracy of the ionisation chambers.

Doelling, Rudolf [Paul Scherrer Institut (PSI), CH-5232 Villigen-PSI (Switzerland)

2006-11-20

311

BOREAS TGB-1 NSA CH4 and CO2 Chamber Flux Data  

NASA Technical Reports Server (NTRS)

The BOREAS TGB-1 team made methane (CH4) and carbon dioxide (CO2) dark chamber flux measurements at the NSA-OJP, NSA-OBS, NSA-BP, and NSA-YJP sites from 16-May-1994 through 13-Sep-1994. Gas samples were extracted approximately every 7 days from dark chambers and analyzed at the NSA lab facility. The data are provided in tabular ASCII files.

Hall, Forrest G. (Editor); Conrad, Sara K. (Editor); Crill, Patrick; Varner, Ruth K.

2000-01-01

312

Contamination Control Assessment of the World's Largest Space Environment Simulation Chamber  

NASA Technical Reports Server (NTRS)

The Space Power Facility s thermal vacuum test chamber is the largest chamber in the world capable of providing an environment for space simulation. To improve performance and meet stringent requirements of a wide customer base, significant modifications were made to the vacuum chamber. These include major changes to the vacuum system and numerous enhancements to the chamber s unique polar crane, with a goal of providing high cleanliness levels. The significance of these changes and modifications are discussed in this paper. In addition, the composition and arrangement of the pumping system and its impact on molecular back-streaming are discussed in detail. Molecular contamination measurements obtained with a TQCM and witness wafers during two recent integrated system tests of the chamber are presented and discussed. Finally, a concluding remarks section is presented.

Snyder, Aaron; Henry, Michael W.; Grisnik, Stanley P.; Sinclair, Stephen M.

2012-01-01

313

Hydrostatic Hyperbaric Chamber Ventilation System  

NASA Technical Reports Server (NTRS)

The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy (HBOT) available in the developing world for the treatment of a variety of medical conditions. Specifically, HBOT is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. HBOT is simply too expensive and too dangerous to implement in the developing world using standard equipment. The HHC technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system to provide controlled pressurization and adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the patient and operating personnel, and physiological considerations. The simple schematic, comprised of easily acquired commercial hardware, supports sustainability.

Sarguisingh, Miriam J.

2012-01-01

314

Medical devices and procedures in the hyperbaric chamber.  

PubMed

The aim of this paper is to present current controversies concerning the safety of medical devices and procedures under pressure in a hyperbaric chamber including: defibrillation in a multiplace chamber; implantable devices during hyperbaric oxygen treatment (HBOT) and the results of a recent European questionnaire on medical devices used inside hyperbaric chambers. Early electrical defibrillation is the only effective therapy for cardiac arrest caused by ventricular fibrillation or pulseless ventricular tachycardia. The procedure of defibrillation under hyperbaric conditions is inherently dangerous owing to the risk of fire, but it can be conducted safely if certain precautions are taken. Recently, new defibrillators have been introduced for hyperbaric medicine, which makes the procedure easier technically, but it must be noted that sparks and fire have been observed during defibrillation, even under normobaric conditions. Therefore, delivery of defibrillation shock in a hyperbaric environment must still be perceived as a hazardous procedure. Implantable devices are being seen with increasing frequency in patients referred for HBOT. These devices create a risk of malfunction when exposed to hyperbaric conditions. Some manufacturers support patients and medical practitioners with information on how their devices behave under increased pressure, but in some cases an individual risk-benefit analysis should be conducted on the patient and the specific implanted device, taking into consideration the patient's clinical condition, the indication for HBOT and the capability of the HBOT facility for monitoring and intervention in the chamber. The results of the recent survey on use of medical devices inside European hyperbaric chambers are also presented. A wide range of non-CE-certified equipment is used in European chambers. PMID:25596835

Kot, Jacek

2014-12-01

315

Chamber dynamic research with pulsed power  

SciTech Connect

In Inertial Fusion Energy (IFE), Target Chamber Dynamics (TCD) is an integral part of the target chamber design and performance. TCD includes target output deposition of target x-rays, ions and neutrons in target chamber gases and structures, vaporization and melting of target chamber materials, radiation-hydrodynamics in target chamber vapors and gases, and chamber conditions at the time of target and beam injections. Pulsed power provides a unique environment for IFE-TCD validation experiments in two important ways: they do not require the very clean conditions which lasers need and they currently provide large x-ray and ion energies.

PETERSON,ROBERT R.; OLSON,CRAIG L.; RENK,TIMOTHY J.; ROCHAU,GARY E.; SWEENEY,MARY ANN

2000-05-15

316

Recent Enhancements to the NASA Langley Structural Acoustics Loads and Transmission (SALT) Facility  

NASA Technical Reports Server (NTRS)

The Structural Acoustics Loads and Transmission (SALT) facility at the NASA Langley Research Center is comprised of an anechoic room and a reverberant room, and may act as a transmission loss suite when test articles are mounted in a window connecting the two rooms. In the latter configuration, the reverberant room acts as the noise source side and the anechoic room as the receiver side. The noise generation system used for qualification testing in the reverberant room was previously shown to achieve a maximum overall sound pressure level of 141 dB. This is considered to be marginally adequate for generating sound pressure levels typically required for launch vehicle payload qualification testing. Recent enhancements to the noise generation system increased the maximum overall sound pressure level to 154 dB, through the use of two airstream modulators coupled to 35 Hz and 160 Hz horns. This paper documents the acoustic performance of the enhanced noise generation system for a variety of relevant test spectra. Additionally, it demonstrates the capability of the SALT facility to conduct transmission loss and absorption testing in accordance with ASTM and ISO standards, respectively. A few examples of test capabilities are shown and include transmission loss testing of simple unstiffened and built up structures and measurement of the diffuse field absorption coefficient of a fibrous acoustic blanket.

Rizzi, Stephen A.; Cabell, Randolph H.; Allen, Albert R.

2013-01-01

317

Scene projection developments in the AEDC space simulation chambers  

NASA Astrophysics Data System (ADS)

Testing system performance early and often under flight conditions is fundamental to managing uncertainty in system performance predictions and reducing system life-cycle cost. As a Department of Defense (DoD) Major Range Test Facility Base (MRTFB), Arnold Engineering Development Center (AEDC) strives to ensure that DoD system performance tests are not limited by test and evaluation capabilities. For over 30 years, the space chambers at AEDC have performed space sensor characterization, calibration, and mission simulation testing on space-based, interceptor, and air-borne sensors. In partnership with the Missile Defense Agency (MDA), AEDC continuously pursues capability upgrades in order to keep pace with evolving sensor technologies. Upgrades to sensor test facilities require rigorous facility characterization and calibration efforts, all of which are routinely included in AEDC's annual activities to ensure quality test data. This paper discusses the status of such upgrades especially with regard to scene projection.

Lowry, H. S., III; Crider, D. H.; Goethert, W. H.; Bertrand, W. T.; Steely, S. L.

2005-05-01

318

Design and testing of a model CELSS chamber robot  

NASA Technical Reports Server (NTRS)

A robot system for use in an enclosed environment was designed and tested. The conceptual design will be used to assist in research performed by the Controlled Ecological Life Support System (CELSS) project. Design specifications include maximum load capacity, operation at specified environmental conditions, low maintenance, and safety. The robot system must not be hazardous to the sealed environment, and be capable of stowing and deploying within a minimum area of the CELSS chamber facility. This design consists of a telescoping robot arm that slides vertically on a shaft positioned in the center of the CELSS chamber. The telescoping robot arm consists of a series of links which can be fully extended to a length equal to the radius of the working envelope of the CELSS chamber. The vertical motion of the robot arm is achieved through the use of a combination ball screw/ball spline actuator system. The robot arm rotates cylindrically about the vertical axis through use of a turntable bearing attached to a central mounting structure fitted to the actuator shaft. The shaft is installed in an overhead rail system allowing the entire structure to be stowed and deployed within the CELSS chamber. The overhead rail system is located above the chamber's upper lamps and extends to the center of the CELSS chamber. The mounting interface of the actuator shaft and rail system allows the entire actuator shaft to be detached and removed from the CELSS chamber. When the actuator shaft is deployed, it is held fixed at the bottom of the chamber by placing a square knob on the bottom of the shaft into a recessed square fitting in the bottom of the chamber floor. A support boot ensures the rigidity of the shaft. Three student teams combined into one group designed a model of the CELSS chamber robot that they could build. They investigated materials, availability, and strength in their design. After the model arm and stand were built, the class performed pre-tests on the entire system. A stability pre-test was used to determine whether the model robot arm would tip over on the stand when it was fully extended. Results showed the stand tipped when 50 Newtons were applied horizontally to the top of the vertical shaft while the arm was fully extended. This proved that it was stable. Another pre-test was the actuator slip test used to determine if there is an adequate coefficient of friction between the actuator drive wheels and drive cable to enable the actuator to fully extend and retract the arm. This pre-test revealed that the coefficient of friction was not large enough to prevent slippage. Sandpaper was glued to the drive wheel and this eliminated the slippage problem. The class preformed a fit test in the CELSS chamber to ensure that the completed robot arm is capable of reaching the entire working envelope. The robot was centered in the chamber and the arm was fully extended to the sides of the chamber. The arm was also able to retract to clear the drain pipes separating the upper and lower plant trays.

Davis, Mark; Dezego, Shawn; Jones, Kinzy; Kewley, Christopher; Langlais, Mike; Mccarthy, John; Penny, Damon; Bonner, Tom; Funderburke, C. Ashley; Hailey, Ruth

1994-01-01

319

Design and testing of a model CELSS chamber robot  

NASA Astrophysics Data System (ADS)

A robot system for use in an enclosed environment was designed and tested. The conceptual design will be used to assist in research performed by the Controlled Ecological Life Support System (CELSS) project. Design specifications include maximum load capacity, operation at specified environmental conditions, low maintenance, and safety. The robot system must not be hazardous to the sealed environment, and be capable of stowing and deploying within a minimum area of the CELSS chamber facility. This design consists of a telescoping robot arm that slides vertically on a shaft positioned in the center of the CELSS chamber. The telescoping robot arm consists of a series of links which can be fully extended to a length equal to the radius of the working envelope of the CELSS chamber. The vertical motion of the robot arm is achieved through the use of a combination ball screw/ball spline actuator system. The robot arm rotates cylindrically about the vertical axis through use of a turntable bearing attached to a central mounting structure fitted to the actuator shaft. The shaft is installed in an overhead rail system allowing the entire structure to be stowed and deployed within the CELSS chamber. The overhead rail system is located above the chamber's upper lamps and extends to the center of the CELSS chamber. The mounting interface of the actuator shaft and rail system allows the entire actuator shaft to be detached and removed from the CELSS chamber. When the actuator shaft is deployed, it is held fixed at the bottom of the chamber by placing a square knob on the bottom of the shaft into a recessed square fitting in the bottom of the chamber floor. A support boot ensures the rigidity of the shaft. Three student teams combined into one group designed a model of the CELSS chamber robot that they could build. They investigated materials, availability, and strength in their design. After the model arm and stand were built, the class performed pre-tests on the entire system. A stability pre-test was used to determine whether the model robot arm would tip over on the stand when it was fully extended. Results showed the stand tipped when 50 Newtons were applied horizontally to the top of the vertical shaft while the arm was fully extended. chamber to ensure that the completed robot arm is capable of reaching the entire working envelope. -The robot was centered in the chamber and the arm was fully extended to the sides of the chamber. The arm was also able to retract to clear the drain pipes separating the upper and lower plant trays.

Davis, Mark; Dezego, Shawn; Jones, Kinzy; Kewley, Christopher; Langlais, Mike; McCarthy, John; Penny, Damon; Bonner, Tom; Funderburke, C. Ashley; Hailey, Ruth

1994-08-01

320

Ion-chamber volume vs. humidity  

Microsoft Academic Search

This letter draws attention to and discusses the significance of findings that A-150 plastic ion chambers are hygroscopic. The resulting changes in volume caused by humidity variations change the radiation sensitivity of the chambers. (ACR)

F. H. Attix

1983-01-01

321

Materials physically tested in variable- environment chamber  

NASA Technical Reports Server (NTRS)

Controlled environment chamber for physical tests of crushable materials encloses both the test specimen and the devices for performing the tests. The chamber may be stepped through a range of changing environment.

Knoell, A. C.

1966-01-01

322

Building a Cloud Chamber (Cosmic Ray Detector)  

NSDL National Science Digital Library

In this activity, students learn about cosmic rays firsthand by building a cloud chamber to detect them. The comprehensive activity includes step-by-step directions for constructing and operating a cloud chamber and ideas for additional experiments.

323

SMOG CHAMBER VALIDATION USING LAGRANGIAN ATMOSPHERIC DATA  

EPA Science Inventory

A method was developed for validating outdoor smog chamber experiments as a means of determining the relationships between oxidant concentrations and its precursors - hydrocarbons and nitrogen oxides. When chamber experiments were performed in a manner that simulated relevant met...

324

MEASUREMENT SENSITIVITY AND ACCURACY VERIFICATION FOR AN ANTENNA MEASUREMENT SYSTEM  

E-print Network

rectangular anechoic chamber (20'L x 10'W x 9'7"H) that has been established at California Polytechnic State system (AMS) built specifically for the Cal Poly State University anechoic chamber. The overall chamber

Arakaki, Dean Y.

325

Outdoor chamber study to test multi-day effects. Volume 2. Environmental chamber data tabulations. Final report, August 1982-August 1984  

SciTech Connect

The smog chamber facilities of the University of California, Riverside were used to collect experimental data to assess the effects of multi-day irradiations on photochemical oxidant formation. This volume contains the printouts of all the data that were collected in the study. These data are suitable for use in developing and testing kinetic mechanisms of photochemical smog formation.

Carter, W.P.L.; Dodd, M.C.; Long, W.D.; Atkinson, R.

1984-12-01

326

Rocket Engine Thrust Chamber Assembly  

NASA Technical Reports Server (NTRS)

A thrust chamber assembly for liquid fueled rocket engines and the method of making it wherein a two-piece mandrel wrapped with a silica tape saturated with a phenolic resin, the tape extending along the mandrel and covering the combustion chamber portion of the mandrel to the throat portion. The phenolic in the tape is cured and the end of the wrap is machined. The remainder of the mandrel is wrapped with a third silica tape. The resin in the third tape is cured and the assembly is machined. The entire assembly is then wrapped with a tow of graphite fibers wetted with an epoxy resin and, after the epoxy resin is cured, the graphite is machined to final dimensions.

Cornelius, Charles S. (Inventor); Counts, Richard H. (Inventor); Myers, W. Neill (Inventor); Lackey, Jeffrey D. (Inventor); Peters, Warren (Inventor); Shadoan, Michael D. (Inventor); Sparks, David L. (Inventor); Lawrence, Timothy W. (Inventor)

2001-01-01

327

Space Chambers for Crop Treatment  

NASA Technical Reports Server (NTRS)

Vacuum chambers, operated by McDonnell Douglas Corporation to test spacecraft, can also be used to dry water-soaked records. The drying temperature is low enough to allow paper to dry without curling or charging. Agricultural crops may also be dried using a spinoff system called MIVAC, which has proven effective in drying rice, wheat, soybeans, corn, etc. The system is energy efficient and can incorporate a sanitation process for destroying insects without contamination.

1985-01-01

328

Acoustic noise control using multiple expansion chambers  

NASA Astrophysics Data System (ADS)

Silencers with expansion chambers are often used to reduce noise in different applications such as HVAC, exhaust systems, and car muffler systems. This study focuses on the effectiveness of multiple expansion chambers in reducing noise. Methods for enhancing silencer designs are realized by utilizing extended tubes, changing expansion chamber cross sectional areas and changing the lengths of the expansion chambers and connecting tubes. General guidelines for design enhancement are provided through this study.

Horoub, Mamon Mohammad

329

The crop growth research chamber  

NASA Technical Reports Server (NTRS)

The Crop Growth Research Chamber (CGRC) has been defined by CELSS principle investigators and science advisory panels as a necessary ground-based tool in the development of a regenerative life support system. The focus of CGRC research will be on the biomass production component of the CELSS system. The ground-based Crop Growth Research Chamber is for the study of plant growth and development under stringently controlled environments isolated from the external environment. The chamber has importance in three areas of CELSS activities: (1) crop research; (2) system control and integration, and (3) flight hardware design and experimentation. The laboratory size of the CGRC will be small enough to allow duplication of the unit, the conducting of controlled experiments, and replication of experiments, but large enough to provide information representative of larger plant communities. Experiments will focus on plant growth in a wide variety of environments and the effects of those environments on plant production of food, water, oxygen, toxins, and microbes. To study these effects in a closed system, tight control of the environment is necessary.

Wagenbach, Kimberly

1993-01-01

330

The crop growth research chamber  

NASA Astrophysics Data System (ADS)

The Crop Growth Research Chamber (CGRC) has been defined by CELSS principle investigators and science advisory panels as a necessary ground-based tool in the development of a regenerative life support system. The focus of CGRC research will be on the biomass production component of the CELSS system. The ground-based Crop Growth Research Chamber is for the study of plant growth and development under stringently controlled environments isolated from the external environment. The chamber has importance in three areas of CELSS activities: (1) crop research; (2) system control and integration, and (3) flight hardware design and experimentation. The laboratory size of the CGRC will be small enough to allow duplication of the unit, the conducting of controlled experiments, and replication of experiments, but large enough to provide information representative of larger plant communities. Experiments will focus on plant growth in a wide variety of environments and the effects of those environments on plant production of food, water, oxygen, toxins, and microbes. To study these effects in a closed system, tight control of the environment is necessary.

Wagenbach, Kimberly

331

Rocket Engine Thrust Chamber Assembly  

NASA Technical Reports Server (NTRS)

A thrust chamber assembly for liquid fueled rocket engines and the method of making it wherein a two-piece mandrel having the configuration of an assembly having a combustion chamber portion connected to a nozzle portion through a throat portion is wrapped with a silica tape saturated with a phenolic resin, the tape extending along the mandrel and covering the combustion chamber portion of the mandrel to the throat portion. The width of the tape is positioned at an angle of 30 to 50 deg. to the axis of the mandrel such that one edge of the tape contacts the mandrel while the other edge is spaced from the mandrel. The phenolic in the tape is cured and the end of the wrap is machined to provide a frusto-conical surface extending at an angle of 15 to 30 deg. with respect to the axis of the mandrel for starting a second wrap on the mandrel to cover the throat portion. The remainder of the mandrel is wrapped with a third silica tape having its width positioned at a angle of 5 to 20 deg. from the axis of the mandrel. The resin in the third tape is cured and the assembly is machined to provide a smooth outer surface. The entire assembly is then wrapped with a tow of graphite fibers wetted with an epoxy resin and, after the epoxy resin is cured, the graphite is machined to final dimensions.

Cornelius, Charles S. (Inventor); Counts, Richard H. (Inventor); Myers, W. Neill (Inventor); Lackey, Jeffrey D. (Inventor); Peters, Warren (Inventor); Shadoan, Michael (Inventor); Sparks, David L. (Inventor); Lawrence, Timothy W. (Inventor)

2001-01-01

332

A sensitive cloud chamber without radioactive sources  

NASA Astrophysics Data System (ADS)

We present a sensitive diffusion cloud chamber which does not require any radioactive sources. A major difference from commonly used chambers is the use of a heat sink as its bottom plate. The result of a performance test of the chamber is given.

Zeze, Syoji; Itoh, Akio; Oyama, Ayu; Takahashi, Haruka

2012-09-01

333

EPA GAS PHASE CHEMISTRY CHAMBER STUDIES  

EPA Science Inventory

Gas-phase smog chamber experiments are being performed at EPA in order to evaluate a number of current chemical mechanisms for inclusion in EPA regulatory and research models. The smog chambers are 9000 L in volume and constructed of 2-mil teflon film. One of the chambers is co...

334

Delay-line readout drift chambers  

NASA Astrophysics Data System (ADS)

Delay-line readout multiwire gas proportional chambers have been constructed that use drift time information to interpolate between anode wires. Position resolutions over the entire active area of the chamber of 150 ?m fwhm are routinely obtained for instantaneous event rates of up to 1 MHz. Chambers with active areas of up to 30 cm by 90 cm have been built.

Atencio, L. G.; Amann, J. F.; Boudrie, R. L.; Morris, C. L.

335

Simple Cloud Chambers Using Gel Ice Packs  

ERIC Educational Resources Information Center

Although cloud chambers are highly regarded as teaching aids for radiation education, school teachers have difficulty in using cloud chambers because they have to prepare dry ice or liquid nitrogen before the experiment. We developed a very simple and inexpensive cloud chamber that uses the contents of gel ice packs which can substitute for dry…

Kamata, Masahiro; Kubota, Miki

2012-01-01

336

Recent Advances in Chamber Science and Technology  

E-print Network

Recent Advances in Chamber Science and Technology Mohamed Abdou April 8, 2002ISFNT-6 San Diego, USA #12;Recent Advances in Chamber Science & Technology OutlineOutline · Highlights of Major World - Experiments - Analysis & Design #12;Highlights of Major World Programs on Chamber (Blanket) Technology

Abdou, Mohamed

337

Mercury Chamber NF-IDS Meeting  

E-print Network

Mercury Chamber Update V. Graves NF-IDS Meeting October 4, 2011 #12;2 Managed by UT-Battelle for the U.S. Department of Energy Mercury Chamber Update Oct 2011 Starting Point: Coil and Shielding Concept IDS120H #12;3 Managed by UT-Battelle for the U.S. Department of Energy Mercury Chamber Update Oct 2011

McDonald, Kirk

338

A Sensitive Cloud Chamber without Radioactive Sources  

ERIC Educational Resources Information Center

We present a sensitive diffusion cloud chamber which does not require any radioactive sources. A major difference from commonly used chambers is the use of a heat sink as its bottom plate. The result of a performance test of the chamber is given. (Contains 8 figures.)

Zeze, Syoji; Itoh, Akio; Oyama, Ayu; Takahashi, Haruka

2012-01-01

339

Uniform-Temperature Walls for Cloud Chambers  

NASA Technical Reports Server (NTRS)

Flat heat pipes rapidly transfer heat to and from experimental volumes. Heat pipe vapor chamber carries heat to and from thermo electric modules. Critical surface acts as evaporator or condenser in cloud physics experiments. Used as walls of spaceborne atmospheric cloud chambers. On Earth, used as isothermal floors for environmental test chambers.

Fleischman, G.

1985-01-01

340

Making a Fish Tank Cloud Chamber  

ERIC Educational Resources Information Center

The cloud chambers described here are large, made from readily available parts, simple to set up and always work. With no source in the chamber, background radiation can be observed. A large chamber means that a long rod containing a weakly radioactive material can be introduced, increasing the chance of seeing decays. Details of equipment and…

Green, Frances

2012-01-01

341

A multifunction ion-irradiation/surface modification ultrahigh vacuum chamber system  

SciTech Connect

A modular ultrahigh vacuum chamber system has been built to facilitate experiments at the Triple Ion Beam Accelerator Facility at the Oak Ridge National Laboratory (ORNL). The system currently consists of three chambers, linked by ultrahigh vacuum valves through which groups of specimens are transferred via a track-type shuttle mechanism. A loading/vapor deposition dual purpose chamber serves not only as a vacuum interlock for loading and unloading groups of specimens, but also as a dual-electron gun-type metal vapor deposition station. The ion-irradiation chamber, located adjacent to the loading chamber, is positioned at the intersection of beam lines from three Van de Graaff accelerators. An Auger surface analyzer with an in situ differentially pumped sputter-gun assembly is located in the third chamber. The chambers are mounted on a frame with airfloat'' pads beneath the feet so that a lateral translation permits the beam lines to be connected to other chambers in the system. The modular assembly concept in conjunction with the lateral mobility and the specimen transfer mechanism enhances the ability to accommodate future expansion in the system. A Hewlett Packard (HP) Vectra PC connected via an IEEE-488 interface to an upgraded HP 3852A controller provides data acquisition and control. 1 ref., 14 figs.

Buhl, R.A.

1991-04-01

342

Optical testing cryogenic thermal vacuum facility  

NASA Technical Reports Server (NTRS)

The construction of a turnkey cryogenic vacuum test facility was recently completed. The facility will be used to measure and record the surface profile of large diameter and 540 kg optics under simulated space conditions. The vacuum test chamber is a vertical stainless steel cylinder with a 3.5 diameter and a 7 m tangent length. The chamber was designed to maximize optical testing quality by minimizing the vibrations between the laser interferometer and the test specimen. This was accomplished by designing the chamber for a high natural frequency and vibration isolating the chamber. An optical test specimen is mounted on a movable presentation stage. During thermal vacuum testing, the specimen may be positioned to + or - 0.00025 cm accuracy with a fine adjustment mechanism. The chamber is evacuated by a close coupled Roots-type blower and rotary vane pump package and two cryopumps. The chamber is equipped with an optically dense gaseous nitrogen cooled thermal shroud. The thermal shroud is used to cool or warm the optical test specimen at a controlled rate. A control system is provided to automatically evacuate the chamber and cooldown the test specimen to the selected control temperature.

Dohogne, Patrick W.; Carpenter, Warren A.

1990-01-01

343

EPA'S HUMAN STUDIES FACILITY AT CHAPEL HILL (BROCHURE)  

EPA Science Inventory

EPA's Human Studies Facility is distiguished by unique, state-of-the art exposure systems designed for studing the health effects of airborne pollutants. The chambers can deliver most gaseous pollutants at precise concentrations and atmospheric conditions. Instrumentation enable...

344

Hydrocarbon-fuel/combustion-chamber-liner materials compatibility  

NASA Technical Reports Server (NTRS)

Results of material compatibility experiments using hydrocarbon fuels in contact with copper-based combustion chamber liner materials are presented. Mil-Spec RP-1, n- dodecane, propane, and methane fuels were tested in contact with OFHC, NASA-Z, and ZrCu coppers. Two distinct test methods were employed. Static tests, in which copper coupons were exposed to fuel for long durations at constant temperature and pressure, provided compatibility data in a precisely controlled environment. Dynamic tests, using the Aerojet Carbothermal Test Facility, provided fuel and copper compatibility data under realistic booster engine service conditions. Tests were conducted using very pure grades of each fuel and fuels to which a contaminant, e.g., ethylene or methyl mercaptan, was added to define the role played by fuel impurities. Conclusions are reached as to degradation mechanisms and effects, methods for the elimination of these mechanisms, selection of copper alloy combustion chamber liners, and hydrocarbon fuel purchase specifications.

Gage, Mark L.

1990-01-01

345

[Taylor and Hill, Incorporated's JSC Cryo Chamber A  

NASA Technical Reports Server (NTRS)

NASA commissioned construction of an environmental simulation test chamber which was completed in 1964 at Johnson Space Center (JSC) in Houston, Texas. The facility, Chamber A, was invaluable for testing spacecraft and satellites before deployment to space. By testing spacecraft in an environment similar to the one they would be functioning in, potential problems could be addressed before launch. A new addition to NASA's observatory inventory is called the James Webb Space Telescope (JWST), after a former Administrator of NASA. The new telescope will have 7 times the mirror area of the Hubble, with a target destination approximately one million miles from earth. Scheduled for launch in 2013, the JWST will allow scientists the ability to see, for the first time, the first galaxies that formed in the early Universe. Pre-launch testing of JWST must be performed in environments that approximate its final target space environment as closely as possible.

Morales, Rito

2008-01-01

346

Status of the construction of the Gluex Forward Drift Chambers  

NASA Astrophysics Data System (ADS)

Currently under construction at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia, the full GlueX detector is designed to study gluonic degrees of freedom through the production of ``hybrid'' mesons with exotic quantum numbers. To accomplish this task the detector requires high acceptance and reasonably good resolution for both charged and neutral particles. The core of the detector is housed within the bore of a 2.0 Tesla solenoidal magnet. Charged particles emanating from the target for angles greater than about 20 degrees with respect to the beam line will be tracked with a straw-tube detector (the Central Drift Chamber). Forward-going charged particles will be detected using the Forward Drift Chambers (FDC). I will describe the design and construction of the FDC and present preliminary resolution measurements.

Taylor, Simon

2013-04-01

347

THE CIRCUMFUSION SYSTEM FOR MULTIPURPOSE CULTURE CHAMBERS  

PubMed Central

A self-contained mechanical system for circulating nutrient fluid through 12 tissue culture chambers is described in detail. This system utilizes nonperforated cellophane membranes in the chambers which separate the circulating nutrient from the tissue culture environments. The nutrient, therefore, is dialyzed through the cellophane of each chamber; some cell products are retained in the microenvironment between the closely apposed cellophane and cover slip, whereas the other cell products move from chamber to chamber in the circulating nutrient. The resultant environmental conditions directed by the circumfusion systems are highly favorable for maintaining the differentiation of chick embryo tissues over protracted periods; a number of micrographs are shown. PMID:10976203

Rose, George G.

1967-01-01

348

Radiated emission measurements conducted in the AST semi-anechoic chamber dual polarization broadband gigahertz field simulator and their verification with the measurements done on the open area test site  

Microsoft Academic Search

This paper addresses an innovative method of measuring radiated emission, using a dual polarization, broadband gigahertz field (BGF) simulator. Verification of emission measurements conducted in the BGF simulator with the measurements done on an open area test site (OATS) is presented

A. S. Podgorski; J. Baran

1998-01-01

349

Chamber propagation physics for heavy ion fusion  

SciTech Connect

Chamber transport is an important area of study for heavy ion fusion. Final focus and chamber-transport are high leverage areas providing opportunities to significantly decrease the cost of electricity from a heavy ion fusion power plant. Chamber transport in two basic regimes is under consideration. In the low chamber density regime ({approx_lt}0.003 torr), ballistic or nearly-ballistic transport is used. Partial beam neutralization has been studied to offset the effects of beam stripping. In the high chamber density regime ({approx_gt}.1 torr), two transport modes (pinched transport and channel transport) are under investigation. Both involve focusing the beam outside the chamber then transporting it at small radius ({approx} 2 mm). Both high chamber density modes relax the constraints on the beam quality needed from the accelerator which will reduce the driver cost and the cost of electricity.

Callahan, D.A.

1995-09-01

350

Thrust chamber material technology program  

NASA Technical Reports Server (NTRS)

This report covers work performed at Pratt & Whitney on development of copper-based materials for long-life, reusable, regeneratively cooled rocket engine thrust chambers. The program approached the goal of enhanced cyclic life through the application of rapid solidification to alloy development, to introduce fine dispersions to strengthen and stabilize the alloys at elevated temperatures. After screening of alloy systems, copper-based alloys containing Cr, Co, Hf, Ag, Ti, and Zr were processed by rapid-solidification atomization in bulk quantities. Those bulk alloys showing the most promise were characterized by tensile testing, thermal conductivity testing, and elevated-temperature, low-cycle fatigue (LFC) testing. Characterization indicated that Cu- 1.1 percent Hf exhibited the greatest potential as an improved-life thrust chamber material, exhibiting LCF life about four times that of NASA-Z. Other alloys (Cu- 0.6 percent Zr, and Cu- 0.6 percent Zr- 1.0 percent Cr) exhibited promise for use in this application, but needed more development work to balance properties.

Andrus, J. S.; Bordeau, R. G.

1989-01-01

351

Educational Facilities.  

ERIC Educational Resources Information Center

This book is a compilation of nearly 100 projects and trends in school design. The projects were submitted for a 1999-2000 competition and focus on a variety of school facilities. These facilities range from early childhood to community colleges, including public, private, and alternative facilities. A jury of architects and educational…

American Inst. of Architects, Washington, DC.

352

INHALATION TOXICOLOGY OF RED AND VIOLET MIXTURES - CHAMBER CONCENTRATION AND PARTICLE SIZE DISTRIBUTION REPORT  

EPA Science Inventory

An inhalation exposure facility was developed at the U.S. EPA, RTP, NC to conduct inhalation exposures of rodents and guinea pigs to dye mixtures used by the U.S. Army in the manufacture of smoke munitions. nitially, an evaluation of the prototype chamber aerosol homogeneity was ...

353

EVALUATION OF THE FLUX CHAMBER METHOD FOR MEASURING VOLATILE ORGANIC EMISSIONS FROM SURFACE IMPOUNDMENTS  

EPA Science Inventory

This research deals with the validation of the flux chamber method for measuring volatile organic emissions from liquid surfaces in treatment, storage and disposal facilities (TSDF). A simulated surface impoundment was constructed so that method precision and accuracy could be de...

354

The Alma Mater Society of U.B.C. Vancouver PLACE: Council Chambers  

E-print Network

The Alma Mater Society of U.B.C. Vancouver PLACE: Council Chambers August 29, 2012 SUB Room 206 to health and wellness. o Asking Council to help in connecting with students. #12;The Alma Mater Society sports. Also club sports; looking at a more robust club structure. Have to look at facilities and decide

Pulfrey, David L.

355

FULL-SCALE CHAMBER INVESTIGATION AND SIMULATION OF AIR FRESHENER EMISSIONS IN THE PRESENCE OF OZONE  

EPA Science Inventory

The paper discusses results of tests, conducted in the EPA large chamber facility, determining emissions and chemical degradation of volatile organic compounds (VOCs) from one electrical plug-in type pine-scented air freshener in the presence of ozone supplied by a device markete...

356

SIZING AND DESIGN OF AN AIR CHAMBER - TRANSIENT MODELING RESULTS AND FIELD TEST COMPARISONS  

Microsoft Academic Search

The Wenatchee Regional Water System was constructed in 1980 to supply all domestic water demands of the Greater Wenatchee, Washington service area. The regional source facility for the system consists of four deep well pumps of various capacity adjacent to the Columbia River, a 7800 gallon air chamber for surge relief, and 10 miles of transmission piping leading to the

Robert C. Elliot; Jim C. P. Liou; Ryan C. Peterson

357

Aging tests of full-scale CMS muon cathode strip chambers  

NASA Astrophysics Data System (ADS)

Two CMS production Cathode Strip Chambers were tested for aging effects in a high-radiation environment at the Gamma Irradiation Facility at CERN. The chambers were irradiated over a large area: in total, about 2.1 m 2 or 700 m of wire in each chamber. The 40% Ar+50% CO 2+10% CF 4 gas mixture was provided by an open-loop gas system for one of the chambers and by a closed-loop re-circulating gas system for the other. After an accumulation of 0.3-0.4 C/cm of a wire, equivalent to about 30-50 years of operation at peak LHC luminosity, no significant changes in gas gain, chamber efficiency and wire signal noise were observed for either of the two chambers. The only consistent signs of aging were a small increase in dark current from ˜2 to ˜10 nA per plane of 600 wires and a decrease of strip-to-strip resistance from 1000 to 10-100 G?. Disassembly of the chambers revealed deposits on the cathode planes, while the anode wires remained fairly clean.

Acosta, D.; Apollinari, G.; Arisaka, K.; Bondar, N.; Breedon, R.; Bujak, A.; Bylsma, B.; Chester, N.; Clare, R.; Cline, D.; Cousins, R.; Cox, T.; Dolinsky, S.; Durkin, S.; Eartly, D.; Ivanov, Yu.; Ferguson, T.; Gavrilov, G.; Gilmore, J.; Gu, J.; Gutay, L.; Hann, F.; Hartmut, R.; Hauser, J.; He, K.; Ignatenko, M.; Ilie, S.; Jiang, C.; Ko, W.; Korytov, A.; Krivshich, A.; Kuznetsova, K.; Layter, J.; Lee, R.; Levtchenko, P.; Ling, T. Y.; Loveless, D.; Lusin, S.; Maeshima, K.; Madorsky, A.; Matthey, C.; Matveev, M.; von der Mey, M.; Mitselmakher, G.; Otwinowski, S.; Padley, P.; Pal, I.; Pischalnikov, Yu.; Prokofiev, O.; Razmyslovich, V.; Reeder, D.; Roberts, J.; Schipunov, L.; Smirnov, I.; Souvorov, V.; Stasko, J.; Sun, H.; Sytnik, V.; Terentyev, N.; Tripathi, M.; Vavilov, S.; Volkov, S.; Vorobyov, A.; Vorobyov, I.; Wang, L.; Yarba, V.; Zhou, L.; Zhu, Z.

2003-12-01

358

30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.  

Code of Federal Regulations, 2010 CFR

...Access to drying chambers, hot gas inlet chambers and ductwork...SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Thermal...Access to drying chambers, hot gas inlet chambers and ductwork...maintenance. Drying chambers, hot gas inlet chambers and all...

2010-07-01

359

Drift chamber tracking with neural networks  

SciTech Connect

We discuss drift chamber tracking with a commercial log VLSI neural network chip. Voltages proportional to the drift times in a 4-layer drift chamber were presented to the Intel ETANN chip. The network was trained to provide the intercept and slope of straight tracks traversing the chamber. The outputs were recorded and later compared off line to conventional track fits. Two types of network architectures were studied. Applications of neural network tracking to high energy physics detector triggers is discussed.

Lindsey, C.S.; Denby, B.; Haggerty, H.

1992-10-01

360

Experimental investigation of a lightweight rocket chamber  

NASA Technical Reports Server (NTRS)

Experiments have been conducted with a jacketed rocket combustion chamber that was fabricated by hydraulic-forming from sheet metal. Rocket combustion chambers made by this method have been used successfully. Runs with these combustion chambers have been made at over-all heat-transfer rates 1.7 Btu per square inch per second with water cooling and also ammonia as a regenerative coolant.

Dalgleish, John E; Tischler, Adelbert O

1953-01-01

361

PSL Icing Facility Upgrade Overview  

NASA Technical Reports Server (NTRS)

The NASA Glenn Research Center Propulsion Systems Lab (PSL) was recently upgraded to perform engine inlet ice crystal testing in an altitude environment. The system installed 10 spray bars in the inlet plenum for ice crystal generation using 222 spray nozzles. As an altitude test chamber, the PSL is capable of simulating icing events at altitude in a groundtest facility. The system was designed to operate at altitudes from 4,000 to 40,000 ft at Mach numbers up to 0.8M and inlet total temperatures from -60 to +15 degF. This paper and presentation will be part of a series of presentations on PSL Icing and will cover the development of the icing capability through design, developmental testing, installation, initial calibration, and validation engine testing. Information will be presented on the design criteria and process, spray bar developmental testing at Cox and Co., system capabilities, and initial calibration and engine validation test. The PSL icing system was designed to provide NASA and the icing community with a facility that could be used for research studies of engine icing by duplicating in-flight events in a controlled ground-test facility. With the system and the altitude chamber we can produce flight conditions and cloud environments to simulate those encountered in flight. The icing system can be controlled to set various cloud uniformities, droplet median volumetric diameter (MVD), and icing water content (IWC) through a wide variety of conditions. The PSL chamber can set altitudes, Mach numbers, and temperatures of interest to the icing community and also has the instrumentation capability of measuring engine performance during icing testing. PSL last year completed the calibration and initial engine validation of the facility utilizing a Honeywell ALF502-R5 engine and has duplicated in-flight roll back conditions experienced during flight testing. This paper will summarize the modifications and buildup of the facility to accomplish these tests.

Griffin, Thomas A.; Dicki, Dennis J.; Lizanich, Paul J.

2014-01-01

362

study on trace contaminants control assembly for sealed environment chamber  

NASA Astrophysics Data System (ADS)

The biological and Physicochemical P C life support technologies are all important parts to establish a human Closed Ecological Life Support System CELSS for long-duration mission The latter has the advantages of lower power consumption lower mass and higher efficiency therefore researchers often incorporate the use of biological systems with P C life support technologies to continuously recycle air water and part of the solid waste stream generated such as the Russian BLSS and the NASA-sponsored Lunar-Mars Life Support Test Project LMLSTP In short these tests were very successful in integrating biological and P C life support technologies for long-duration life support Therefore we should use a combination of integrated biological with P C life support technologies in a human CELSS Human construction materials plants animals and soils release much trace toxic gases in a CELSS and they will inhibit plant growth and badly affect human health when their concentrations rise over their threshold levels The effect of biological trace contaminant control technologies is slower especially for a human sealed chamber because human produce much more methane and other contaminants A regenerative Trace Contaminant Control Subsystem TCCS with P C technology is a more important part in this case to control quickly the airborne contaminants levels and assure human in good condition in a sealed chamber This paper describes a trace contaminant control test facility incorporated a 8 m3 sealed environment chamber a regenerative TCCS with P C

Pang, L. P.; Wang, J.; Liu, L. K.; Liu, H.

363

Modeling smog chamber measurements of vehicle exhaust VOC reactivities  

SciTech Connect

Vehicle exhaust VOC reactivities, measured at GM`s smog chamber facility, have been modeled using the SAPRC93 photochemical mechanism. The vehicle exhaust mixtures were generated by a single vehicle run over a portion of the Federal Test Procedure using three Auto/Oil reformulated test gasolines. For each run, up to 156 individual VOC species were identified. Initial HONO concentrations are needed to simulate reactivity measurement runs. (HONO is expected to be generated in a Tedlar bag holding the exhaust sample prior to its transfer to the smog chambers.) Measured and simulated relative incremental reactivities for the three exhaust mixtures are highly consistent. However, measured relative incremental reactivities are more sensitive to fuel effects than simulated ones. The maximum incremental reactivity (MIR)-based relative incremental reactivities, derived from individual species concentrations and MIR factors, are very close to simulated ones. A number of sensitivity simulation runs have been carried out to investigate the impact of HONO and other variables. Results show that relative reactivities of actual vehicle exhaust emissions can be measured by chamber runs in spite of the HONO effect.

Chang, T.Y.; Nance, B.I. [Ford Motor Co., Dearborn, MI (United States). Ford Research Lab.; Kelly, N.A. [General Motors R and D Center, Warren, MI (United States)

1997-12-31

364

Response of ionization chamber based pocket dosimeter to beta radiation.  

PubMed

Quantitative estimate of the response of ionization chamber based pocket dosimeters (DRDs) to various beta sources was performed. It has been established that the ionization chamber based pocket dosimeters do not respond to beta particles having energy (Emax)<1 MeV and same was verified using (147)Pm, (85)Kr and (204)Tl beta sources. However, for beta particles having energy >1 MeV, the DRDs exhibit measureable response and the values are ~8%, ~14% and ~27% per mSv for natural uranium, (90)Sr/(90)Y and (106)Ru/(106)Rh beta sources respectively. As the energy of the beta particles increases, the response also increases. The response of DRDs to beta particles having energy>1 MeV arises due to the fact that the thickness of the chamber walls is less than the maximum range of beta particles. This may also be one of the reasons for disparity between doses measured with passive/legal dosimeters (TLDs) and DRDs in those situations in which radiation workers are exposed to mixed field of gamma photons and beta particles especially at uranium processing plants, nuclear (power and research) reactors, waste management facilities and fuel reprocessing plants etc. The paper provides the reason (technical) for disparity between the doses recorded by TLDs and DRDs in mixed field of photons and beta particles. PMID:23978508

Kumar, Munish; Gupta, Anil; Pradhan, S M; Bakshi, A K; Chougaonkar, M P; Babu, D A R

2013-12-01

365

An airborne isothermal haze chamber  

NASA Technical Reports Server (NTRS)

Thermal gradient diffusion cloud chambers (TGDCC) are used to determine the concentrations of cloud condensation nuclei (CCN) with critical supersaturations greater than or equal to about 0.2%. The CCN concentrations measured with the airborne IHC were lower than theoretically predicted by factors ranging between 7.9 and 9.0. The CCN concentrations measured with the airborne IHC were lower than the concentrations measured with the larger laboratory IHC's by factors ranging between 3.9 and 7.5. The bounds of the supersaturation ranges of the airborne IHC and the CSU-Mee TGDCC do not overlap. Nevertheless, the slopes of the interpolated data between the bounds agree favorably with the theoretical slopes.

Hindman, E. E.

1981-01-01

366

A preliminary inter-centre comparison study for photon, thermal neutron and epithermal neutron responses of two pairs of ionisation chambers used for BNCT  

Microsoft Academic Search

The dual ionisation chamber technique is the recommended method for mixed field dosimetry of epithermal neutron beams. This paper presents initial data from an ongoing inter-comparison study involving two identical pairs of ionisation chambers used at the BNCT facilities of Petten, NL and of the University of Birmingham, UK. The goal of this study is to evaluate the photon, thermal

Antoaneta Roca; Yuan-Hao Liu; Cecile Wojnecki; Stuart Green; Sander Nievaart; Zamir Ghani; Ray Moss

2009-01-01

367

Engineering verification of the biomass production chamber  

NASA Technical Reports Server (NTRS)

The requirements for life support systems, both biological and physical-chemical, for long-term human attended space missions are under serious study throughout NASA. The KSC 'breadboard' project has focused on biomass production using higher plants for atmospheric regeneration and food production in a special biomass production chamber. This chamber is designed to provide information on food crop growth rate, contaminants in the chamber that alter plant growth requirements for atmospheric regeneration, carbon dioxide consumption, oxygen production, and water utilization. The shape and size, mass, and energy requirements in relation to the overall integrity of the biomass production chamber are under constant study.

Prince, R. P.; Knott, W. M., III; Sager, J. C.; Jones, J. D.

1992-01-01

368

Advanced thrust chambers for miniaturized engines  

NASA Astrophysics Data System (ADS)

The general approach in previous Kinetic Kill Vehicle (KKV) thruster design consisted of separate lightweight and low-cost thrust chambers, injectors and valves. A series of programs including hot-fire testing and hover flight tests has led to the design of a new generation liquid bipropellant thruster with an integrated chamber/injector/valve thruster design. System analyses indicate the composite approach provides thermal management for thrust chambers and that an integral injector/valve contributes to a high thrust to weight ratio thruster. Past experience and development test results of an Advanced Composite material are described. Advanced Composite material selection, chamber fabrication and testing program are discussed. The thrust chambers were evaluated on the basis of oxidation resistance, durability, permeability through the chambers walls, strength and performance with excellent results in all areas. Excellent thrust chamber durability was demonstrated with no measurable erosion after extensive accumulated hot-fire time at high chamber pressure. Results to date indicate that the existing technology provides producible, highly durable chambers for KKV applications.

Pavlinsky, Joseph

1992-07-01

369

The Mark II Vertex Drift Chamber  

SciTech Connect

We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 {mu}m spatial resolution and <1000 {mu}m track-pair resolution in pressurized CO{sub 2} gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO{sub 2} mixtures are presented. 10 refs., 12 figs., 1 tab.

Alexander, J.P.; Baggs, R.; Fujino, D.; Hayes, K.; Hoard, C.; Hower, N.; Hutchinson, D.; Jaros, J.A.; Koetke, D.; Kowalski, L.A.

1989-03-01

370

Biases in methane chamber measurements in peatlands  

NASA Astrophysics Data System (ADS)

The paper presents results of CH4 emission measurements at peatland with the application of the dynamic chamber technique. The measurements were conducted in two types of chambers differing in shape, height, volume and technology used to assure their tightness. The study tested how the following factors: 1) forced chamber headspace mixing or its absence, 2) mistakes of the person conducting measurements, 3) improper application of linear technique for calculating CH4 fluxes, and 4) simulated air sampling typical for static chambers, influence the significance of errors and the underestimation rate of CH4 fluxes measured in situ. It was indicated that chamber headspace mixing allows estimating methane fluxes with a smaller error than in the case of measurements conducted without mixing, and CH4 fluxes in such conditions can be 47 to 58% higher (depending on the chamber type) than in a chamber without fans. Using dynamic chambers and a fast analyzer to measure methane fluxes allows shortening the methane measurement process to a few minutes. On the other hand, using static chambers for methane flux measurements may lead to 70% underestimation of the calculated flux.

Juszczak, R.

2013-03-01

371

Neutronics analysis of the Laboratory Microfusion Facility  

SciTech Connect

The radiological safety hazards of the experimental area (EA) for the proposed Inertial Confinement Fusion (ICF) Laboratory Microfusion Facility (LMF) have been examined. The EA includes those structures required to establish the proper pre-shot environment, point the beams, contain the pellet yield, and measure many different facets of the experiments. The radiation dose rates from neutron activation of representative target chamber materials, the laser beam tubes and the argon gas they contain, the air surrounding the chamber, and the concrete walls of the experimental area are given. Combining these results with the allowable dose rates for workers, we show how radiological considerations affect access to the inside of the target chamber and to the diagnostic platform area located outside the chamber. Waste disposal and tritium containment issues are summarized. Other neutronics issues, such as radiation damage to the final optics and neutron heating of materials placed close to the target, are also addressed. 16 refs., 2 figs., 1 tab.

Tobin, M.T.; Singh, M.S.; Meier, W.R.

1988-09-19

372

LABORATORY ANIMAL FACILITIES STANDARD OPERATING PROCEDURE  

E-print Network

Faculty, students, and technicians who work with live animals in their labs or testing rooms. 2.0 Procedure 2.1 All equipment, transfer boxes, and holding/testing chambers used for animal research1.C.7 LABORATORY ANIMAL FACILITIES STANDARD OPERATING PROCEDURE FOR SANITATION OF RESEARCH

Krovi, Venkat

373

Use of an ignition facility for fusion propulsion experiments  

Microsoft Academic Search

The utilization of an ignition facility for a fusion propulsion experiment is proposed. An experimental setup in the facility chamber is presented along with plasma behaviors calculated by a three-dimensional hybrid code. The plasma instability in a magnetic nozzle is examined and the effect on thrust efficiency is discussed. Implications of this experiment to fields other than propulsion are also

H Nakashima; Y Nagamine; N Yoshimi; Y. P Zakharov; A. G Ponomarenko

1999-01-01

374

ACOUSTIC BEHAVIOUR OF ELLIPTICAL CHAMBER MUFFLERS  

Microsoft Academic Search

The present work studies in detail the acoustic behaviour of mufflers with elliptical cross-section. The effect of the chamber length and the location of the inlet and outlet ports is considered. In addition, the eccentricity of the ellipse is taken into account, since it generates important discrepancies with respect to those results obtained for the case of circular chambers, mainly

F. D. DENIA; J. ALBELDA; F. J. FUENMAYOR; A. J. TORREGROSA

2001-01-01

375

Space Simulation Chamber Rescues Water Damaged Books.  

ERIC Educational Resources Information Center

More than 4,000 valuable water-damaged books were restored by using a space-simulation chamber at the Lockheed Missile and Space Company. It was the fifth time that the chamber has been used for the restoration of valuable books and documents. (Author/MLF)

American School and University, 1981

1981-01-01

376

Multispecimen dual-beam irradiation damage chamber  

Microsoft Academic Search

An irradiation damage chamber that can be used to rapidly simulate fast neutron damage in fission or fusion materials has been designed and constructed. The chamber operates in conjunction with dual Van de Graaff accelerators at ORNL to simulate a wide range of irradiation conditions, including pulsed irradiation. Up to six experiments, each with up to nine 3-mm disk specimens,

N. H. Packan; R. A. Buhl

1980-01-01

377

Performance of the continuous flow diffusion chambers  

NASA Technical Reports Server (NTRS)

A brief comparative description is made of the chambers. Overall, comparisons for the various types of experiments - monodisperse, polydisperse and ambient aerosol - showed agreement among these chambers to within 15% in most cases. A careful analysis of the results indicated that a proper accounting of certain parameters would bring about much closer agreement among four of these instruments.

Hudson, J. G.; Alofs, D. J.

1982-01-01

378

Compositional and thermal convection in magma chambers  

Microsoft Academic Search

Magma chambers cool and crystallize at a rate determined by the heat flux from the chamber. The heat is lost predominantly through the roof, whereas crystallization takes place mainly at the floor. Both processes provide destabilizing buoyancy fluxes which drive highly unsteady, chaotic convection in the magma. Even at the lowest cooling rates the thermal Rayleigh number Ra is found

Daniel Martin; Ross W. Griffiths; Ian H. Campbell

1987-01-01

379

Results from the MAC Vertex chamber  

SciTech Connect

The design, construction, and performance characteristics of a high precision gaseous drift chamber made of thin walled proportional tubes are described. The device achieved an average spatial resolution of 45 ..mu..m in use for physics analysis with the MAC detector. The B-lifetime result obtained with this chamber is discussed.

Nelson, H.N.

1987-05-01

380

Performance tests on a novel vapor chamber  

Microsoft Academic Search

The performance of a novel vapor chamber is tested in this study. In this vapor chamber, parallel grooves are made on the inner surface of the top plate, with inter-groove openings, to replace the conventional porous wick. To the inner surface of the bottom plate is sintered a layer of porous wick as the evaporator. The peaks of the groove

Kuo-Chun Hsieh; Shwin-Chung Wong

2009-01-01

381

A novel vapor chamber and its performance  

Microsoft Academic Search

The performance of a novel vapor chamber is tested in this study. In this vapor chamber, parallel grooves are made on the inner surface of the top plate, with inter-groove openings, to replace the conventional porous wick. To the inner surface of the bottom plate is sintered a layer of porous wick as the evaporator. The peaks of the groove

Shwin-Chung Wong; Kuo-Chun Hsieh; Jia-Da Wu; Wei-Lun Han

2010-01-01

382

Dual-chamber inflatable oil boom  

SciTech Connect

An elongated floating material containment boom section is described having a normally vertical ballasted skirt depending from flotation means, and convertible from a flattened collapsed condition to a deployable condition wherein buoyancy chamber means extending along the upper edge of said skirt are inflated to expanded buoyant configuration, including: a gas-impervious sleeve extending along the upper edge of said normally vertical skirt forming a first outer collapsible and inflatable flotation chamber, a first inflation valve connecting the interior of said sleeve with the ambient atmosphere, through which gas under pressure may be introduced into said sleeve to inflate said first buoyant outer flotation chamber, elongated gas-impervious tube means positioned inside said outer flotation chamber and forming second collapsible and inflatable internal flotation bladder chamber means, second inflation valve means connecting the interior of said bladder means through said outer flotation chamber to the ambient atmosphere through which gas under pressure may be introduced into said bladder means to inflate it forming said second flotation chamber means inside said outer flotation chamber.

Blair, R.M.; Tedeschi, E.T.

1993-08-24

383

The Meditation Chamber: Towards Self-Modulation  

E-print Network

The Meditation Chamber: Towards Self-Modulation Chris Shaw Simon Fraser University, Canada Diane The Meditation Chamber is an immersive virtual environment (VE), initially created to enhance and augment the existing methods of training users how to meditate, and by extension, to realize the benefits from

Shaw, Chris

384

Incinerator system arrangement with dual scrubbing chambers  

SciTech Connect

An incinerator arrangement is described comprising: an incinerator housing located near the lowest point in a building, the housing containing incinerator elements therein; a chute-flue having a first end in communication with the incinerator housing, a second end at the top of the building for evacuation of combustion gases to the atmosphere therethrough, and at least one intermediately located waste disposal opening through which waste is dropped into the incinerator housing; the incinerator elements including: a main combustion chamber, an opening between the main combustion chamber and the first end of the chute-flue and a flue-damper covering the opening. The flue-damper is biased in a closed position and being operable by the weight of waste to admit the waste into the combustion chamber; a scrubbing chamber located exteriorly along the top of the combustion chamber and having a first opening into the combustion chamber and a second opening into the chute-flue; and water spraying means in the scrubbing chamber for directing a water spray at the combustion gases to wash particulate matter from the gases before the gases enter the chute-flue whereby the water spraying means which are located adjacent the combustion chamber are protected against freezing and the elements.

Domnitch, I.

1987-01-13

385

SRMAFTE facility checkout model flow field analysis  

NASA Astrophysics Data System (ADS)

The Solid Rocket Motor Air Flow Equipment (SRMAFTE) facility was constructed for the purpose of evaluating the internal propellant, insulation, and nozzle configurations of solid propellant rocket motor designs. This makes the characterization of the facility internal flow field very important in assuring that no facility induced flow field features exist which would corrupt the model related measurements. In order to verify the design and operation of the facility, a three-dimensional computational flow field analysis was performed on the facility checkout model setup. The checkout model measurement data, one-dimensional and three-dimensional estimates were compared, and the design and proper operation of the facility was verified. The proper operation of the metering nozzles, adapter chamber transition, model nozzle, and diffuser were verified. The one-dimensional and three-dimensional flow field estimates along with the available measurement data are compared.

Dill, Richard A.; Whitesides, Harold R.

1992-07-01

386

A new gun facility dedicated to performing shock physics and terminal ballistics experiments  

NASA Astrophysics Data System (ADS)

A new building has been constructed to house various powder and single-stage and two-stage gas guns at the Naval Surface Warfare Center, Indian Head Division. Guns previously located at the Naval Research Laboratory and the former White Oak Site of the Naval Surface Warfare Center have been relocated here. Most of the guns are mounted on moveable pedestals to allow them to be shot into various chambers. The facility includes a concrete blast chamber, a target chamber/catch tank for flyer plate experiments, and a target chamber outfitted for terminal ballistics measurements. This paper will discuss the capabilities of this new facility.

Zakraysek, Alan J.; Sutherland, Gerrit T.; Sandusky, Harold D.; Strange, David

2000-04-01

387

Advanced tube-bundle rocket thrust chamber  

NASA Technical Reports Server (NTRS)

An advanced rocket thrust chamber for future space application is described along with an improved method of fabrication. Potential benefits of the concept are improved cyclic life, reusability, and performance. Performance improvements are anticipated because of the enhanced heat transfer into the coolant which will enable higher chamber pressure in expander cycle engines. Cyclic life, reusability and reliability improvements are anticipated because of the enhanced structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber with a tube-bundle of high conductivity copper or copper alloy tubes, and the bonding of these tubes by an electroforming operation. Further, the method of fabrication reduces chamber complexity by incorporating manifolds, jackets, and structural stiffeners while having the potential for thrust chamber cost and weight reduction.

Kazaroff, John M.; Pavli, Albert J.

1990-01-01

388

Aging effect in the BESIII drift chamber  

E-print Network

As the main tracking detector of BESIII, the drift chamber works for accurate measurements of the tracking and the momentum of the charged particles decayed from the reaction of BEPCII e+ and e-. After operation six years, the drift chamber is suffering from aging problems due to huge beam related background. The gains of the cells in the first ten layers experience an obvious decrease, reaching a maximum of about 29% for the first layer cells. Two calculation methods for the gains change (Bhabha events and accumulated charges with 0.3% aging ratio for inner chamber cells) get almost the same results. For the Malter effect encountered by the inner drift chamber in Jan., 2012, about 0.2% water vapor was added to MDC gas mixture to solve this cathode aging problem. These results provide an important reference for MDC operation high voltage setting and the upgrade of the inner drift chamber.

M. Y. Dong; Q. L. Xiu; L. H. Wu; Z. Wu; Z. H. Qin; P. Shen; F. F. An; X. D. Ju; Y. Liu; K. Zhu; Q. Ouyang; Y. B. Chen

2015-04-18

389

Aging effect in the BESIII drift chamber  

E-print Network

As the main tracking detector of BESIII, the drift chamber works for accurate measurements of the tracking and the momentum of the charged particles decayed from the reaction of BEPCII e+ and e-. After operation six years, the drift chamber is suffering from aging problems due to huge beam related background. The gains of the cells in the first ten layers experience an obvious decrease, reaching a maximum of about 29% for the first layer cells. Two calculation methods for the gains change (Bhabha events and accumulated charges with 0.3% aging ratio for inner chamber cells) get almost the same results. For the Malter effect encountered by the inner drift chamber in Jan., 2012, about 0.2% water vapor was added to MDC gas mixture to solve this cathode aging problem. These results provide an important reference for MDC operation high voltage setting and the upgrade of the inner drift chamber.

Dong, M Y; Wu, L H; Wu, Z; Qin, Z H; Shen, P; An, F F; Ju, X D; Liu, Y; Zhu, K; Ouyang, Q; Chen, Y B

2015-01-01

390

An atmospheric exposure chamber for small animals  

NASA Technical Reports Server (NTRS)

The purpose of this project was to design a long-term environmental exposure chamber for small animals. This chamber is capable of producing hypoxic, normoxic and hyperoxic atmospheres which are closely regulated. The chamber, which is of the recycling type, is fashioned after clear plastic germ-free isolators. Oxygen concentration is set and controlled by a paramagnetic O2 analyzer and a 3-way solenoid valve. In this way either O2 or N2 may be provided to the system by way of negative O2 feedback. Relative humidity is maintained at 40-50 percent by a refrigeration type dryer. Carbon dioxide is absorbed by indicating soda lime. A diaphragm pump continuously circulates chamber gas at a high enough flow rate to prevent buildup of CO2 and humidity. This chamber has been used for numerous studies which involve prolonged exposure of small animals to various O2 concentrations.

Glaser, R. M.; Weiss, H. S.; Pitt, J. F.; Grimard, M.

1982-01-01

391

Aging in large CDF tracking chambers  

SciTech Connect

The experience of the Collider Detector at Fermilab (CDF) with aging in the large axial drift chamber responsible for tracking in the central region is presented. Premature aging in the Run 1 chamber was observed after only 0.02 C/cm. After cleaning much of the gas system and making modifications to reduce aerosols from the alcohol bubbler, the observed aging rate fell dramatically in test chambers. Considerable effort has been made to better understand the factors that affect aging since the replacement chamber for Run 2 will accumulate about 1.0 C/cm. Current test chambers using the full CDF gas system show aging rates of less than 5%/C/cm.

M. Binkley et al.

2001-03-19

392

Secondary combustion chamber for an incinerator  

SciTech Connect

This patent describes in an incinerator apparatus, an incinerator to burn waste material, a stack connected to the incinerator for discharging waste gases of combustion, a housing defining a secondary combustion chamber having an inlet connected to the upper end of the stack and having an outlet, at least one tube formed of ceramic material extending transversely of the chamber. The tube having an outer end connected to the housing and having a closed inner end. The tube extending more than one half the cross sectional dimension of the chamber, means for supplying air to the outer end of the tube. The tube having a plurality of outlet ports with the axes of the ports disposed generally normal to the flow of waste gases through the chamber, air introduced into the tube being discharged through the ports to provide an air curtain extending, generally transversely across the chamber.

Hoskinson, G.H.

1989-11-28

393

Characterizing the acoustic properties of the Jet Lab at the National Center for Physical Acoustics  

NASA Astrophysics Data System (ADS)

Aerodynamic noise has been a problem since the first use of the jet engine for military aircraft in World War II. For further uses of the jet engine to be possible, problems due to jet noise must be researched and addressed. Anechoic chambers were proposed as a testing facility for research in aerodynamic noise because of their supposed free-field characteristics. The international standard ISO 3745-1977 was introduced to determine whether the facilities could be considered anechoic, semi-anechoic, or neither. An experiment was designed to determine at what frequencies the National Center for Physical Acoustics' Jet Lab Facility is non-anechoic, semi-anechoic, or anechoic. To comply with the guidelines of ISO 3745- 1977, three sources were designed and tested at frequencies from 25 Hz to 16000 Hz. The voltages were acquired at each frequency to calculate the sound pressure level and determine if the calculated values are within the allowed tolerance of the inverse square law.

Lieblong, Joshua Anderson

394

TRIDENT high-energy-density facility experimental capabilities and diagnostics  

SciTech Connect

The newly upgraded TRIDENT high-energy-density (HED) facility provides high-energy short-pulse laser-matter interactions with powers in excess of 200 TW and energies greater than 120 J. In addition, TRIDENT retains two long-pulse (nanoseconds to microseconds) beams that are available for simultaneous use in either the same experiment or a separate one. The facility's flexibility is enhanced by the presence of two separate target chambers with a third undergoing commissioning. This capability allows the experimental configuration to be optimized by choosing the chamber with the most advantageous geometry and features. The TRIDENT facility also provides a wide range of standard instruments including optical, x-ray, and particle diagnostics. In addition, one chamber has a 10 in. manipulator allowing OMEGA and National Ignition Facility (NIF) diagnostics to be prototyped and calibrated.

Batha, S. H.; Aragonez, R.; Archuleta, F. L.; Archuleta, T. N.; Benage, J. F.; Cobble, J. A.; Cowan, J. S.; Fatherley, V. E.; Flippo, K. A.; Gautier, D. C.; Gonzales, R. P.; Greenfield, S. R.; Hegelich, B. M.; Hurry, T. R.; Johnson, R. P.; Kline, J. L.; Letzring, S. A.; Loomis, E. N.; Lopez, F. E.; Luo, S. N. [Los Alamos National Laboratory, P.O. Box 1663, MS E526, Los Alamos, New Mexico 87545 (United States)] (and others)

2008-10-15

395

04/22/02 EGS G6 2002 1 STABILITY OF GLOBAL GEODETIC  

E-print Network

. · So many years, use of anechoic chamber measurements for ground antennas causes large scale change (14. · Recent insitu absolute phase center calibrations match most of the previous anechoic chamber results 04

Herring, Thomas

396

SCHOOLOFARCHITECTURE Table of Contents  

E-print Network

activities include a testing room with a Hemi-anechoic chamber, the Binaural Listening and Auralization test, scale-model reverberation and anechoic chambers, specialized acoustic laboratory equipment, advanced

Varela, Carlos

397

Parameters of Vowel Quality GORDON E. PETERSON  

E-print Network

such amplitude sections. Vowel Matches. For the major por- tion of the study, speakers in the anechoic chamber recognized the assigned task. Each subject and the experimenter worked together in the anechoic chamber

Allen, Jont

398

SCHOOLOFARCHITECTURE Table of Contents  

E-print Network

that enhance school activities include a testing room with a Hemi-anechoic chamber, the Binaural Listening and investigation, scale-model reverberation and anechoic chambers, specialized acoustic laboratory equipment

Varela, Carlos

399

The AlloSphere: for Scientific  

E-print Network

, making it one of the largest near-to- anechoic chambers in the world. In a perfect anechoic space, sound perspective. Stand- ing inside this chamber are two hemispheres constructed of perforated aluminum designed

Hollerer, Tobias

400

In this paper, we represent numerical results which, validate our former work on the hydrodynamic effect (nonlinear)  

E-print Network

-band in our anechoic chamber (E³I²-EA3876- laboratory of Ensta bretagne); of the breaking waves profiles in an anechoic chamber [5]. However, the surface scattering by breaking waves "non- Bragg" is not enough studied

Paris-Sud XI, Université de

401

Outdoor chamber study to test multi-day effects. Volume 3. Documentation for computer-readable environmental chamber data. Final report, August 1982-August 1984  

SciTech Connect

The smog chamber facilities of the University of California, Riverside were used to collect experimental data to assess the effects of multi-day irradiations on photochemical oxidant formation. This volume includes documentation on the computer-readable magnetic tape that contains all the data collected in the study. The tape is suitable for use by modelers to develop and test kinetic mechanisms of photochemical smog formation.

Carter, W.P.L.; Dodd, M.C.; Long, W.D.; Atkinson, R.

1984-12-01

402

Nuclear Facilities  

NSDL National Science Digital Library

In order to produce nuclear weapons, each country must have facilities to produce and refine the nuclear materials, conduct research on weapon design, and store the completed weapons. The interactives in this collection allow you to explore the nuclear facilities of the nuclear powers (both declared and undeclared).

Christopher Griffith

403

RCRA FACILITIES  

EPA Science Inventory

Points represent facilities that are regulated by the EPA under the Resource Conservation and Recovery Act (RCRA). Facilities regulated under RCRA generate, dispose of, treate or transport hazardous waste. RCRA is a law enacted by Congress in 1976 and amended in 1984 to include ...

404

IFE thick liquid wall chamber dynamics: Governing mechanisms andmodeling and experimental capabilities  

SciTech Connect

For thick liquid wall concepts, it is important to understand the different mechanisms affecting the chamber dynamics and the state of the chamber prior to each shot a compared with requirements from the driver and target. These include ablation mechanisms, vapor transport and control, possible aerosol formation, as well as protective jet behavior. This paper was motivated by a town meeting on this subject which helped identify the major issues, assess the latest results, review the capabilities of existing modeling and experimental facilities with respect to addressing remaining issues, and helping guide future analysis and R&D efforts; the paper covers these exact points.

Raffray, A.R.; Meier, W.; Abdel-Khalik, S.; Bonazza, R.; Calderoni, P.; Debonnel, C.S.; Dragojlovic, Z.; El-Guebaly, L.; Haynes,D.; Latkowski, J.; Olson, C.; Peterson, P.F.; Reyes, S.; Sharpe, P.; Tillack, M.S.; Zaghloul, M.

2005-01-24

405

Numerical study of air chamber for oscillating water column wave energy convertor  

NASA Astrophysics Data System (ADS)

Oscillating Water Column (OWC) wave energy converting system is one of the most widely used facilities all over the world. The air chamber is utilized to convert the wave energy into the pneumatic energy. The numerical wave tank based on the two-phase VOF model is established in the present study to investigate the operating performance of OWC air chamber. The RANS equations, standard k-? turbulence model and dynamic mesh technology are employed in the numerical model. The effects of incident wave conditions and shape parameters on the wave energy converting efficiency are studied and the capability of the present numerical wave tank on the corresponding engineering application is validated.

Liu, Zhen; Hyun, Beom-Soo; Hong, Keyyong

2011-03-01

406

Construction of a fast ionization chamber for high-rate particle identification  

NASA Astrophysics Data System (ADS)

A new gas-filled ionization chamber for high count rate particle identification has been constructed and commissioned at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL). To enhance the response time of the ionization chamber, a design utilizing a tilted entrance window and tilted electrodes was adopted, which is modified from an original design by Kimura et al. [1]. A maximum counting rate of ~700,000 particles per second has been achieved. The detector has been used for several radioactive beam measurements performed at the HRIBF.

Chae, K. Y.; Ahn, S.; Bardayan, D. W.; Chipps, K. A.; Manning, B.; Pain, S. D.; Peters, W. A.; Schmitt, K. T.; Smith, M. S.; Strauss, S. Y.

2014-07-01

407

BOREAS TGB-3 CH4 and CO2 Chamber Flux Data over NSA Upland Sites  

NASA Technical Reports Server (NTRS)

The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-3) team collected methane and carbon dioxide (CH4, CO2) chamber flux measurements at the Northern Study Area (NSA) Fen, Old Black Spruce (OBS), Young Jack Pine (YJP), and auxiliary sites along Gillam Road and the 1989 burn site. Gas samples were extracted from chambers and analyzed at the NSA lab facility approximately every 7 days during May to September 1994 and June to October 1996. The data are provided in tabular ASCII files.

Savage, Kathleen; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor); Moore, Tim R.

2000-01-01

408

Automated Transmission Loss Measurement in the Structural Acoustic Loads and Transmission Facility at NASA Langley Research Center  

NASA Technical Reports Server (NTRS)

A technique to measure the radiated acoustic intensity and transmission loss of panels is documented in this paper. This facility has been upgraded to include a test fixture that scans the acoustic intensity radiated from a panel on the anechoic receiving room side of the transmission loss window. The acoustic intensity incident on the panel from the reverberant side of the transmission loss window is estimated from measurements made using six stationary microphones in the reverberant source room. From the measured incident and radiated intensity, the sound power transmission loss is calculated. The setup of the facility and data acquisition system are documented. A transmission loss estimate of a typical panel is shown. The measurement-to-measurement and setup-to-setup repeatability of the transmission loss estimate are assessed. Conclusions are drawn about the ability to measure changes in transmission loss due to changes in panel construction.

Klos, J.; Brown, S. A.

2002-01-01

409

Performance of NIRS Thoron Chamber System  

SciTech Connect

In order to carry out thoron sensitivity test for passive radon detectors, a thoron chamber system has been set up at NIRS, Japan. The thoron chamber system consists of four components: the exposure, monitoring, calibration, and humidity control systems, which was mounted in this study due to humidity dependence on the thoron concentration emanated from lantern mantles as the thoron source. The thoron concentration in the thoron chamber is controlled by humidity passed through the thoron source and the weight of the lantern mantle.

Sorimachi, Atsuyuki; Tokonami, Shinji; Takahashi, Hiroyuki; Kobayashi, Yosuke [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan)

2008-08-07

410

Sample chambers with mother-daughter mode  

SciTech Connect

A set of eight stand-alone sample chambers with a common interface were constructed at LBNL for improved detection of alpha and fission decay chains over currently used designs. The stainless steel chambers (see Figure 1 for a schematic and Figure 2 for a photograph of a completed chamber) were constructed to allow for low background detection of a daughter event by removal of the sample following the detection of a parent event. This mother-daughter mode of operation has been utilized successfully with our Merry-go-Round (MG) detection system [Gregorich 1994].

Wilk, P.A.; Gregorich, K.E.; Hoffman, D.C.

2001-07-12

411

The next step in chemical propulsion: Oxide-iridium/rhenium combustion chambers  

SciTech Connect

Chemical propulsion systems are currently limited by materials issues. Until recently, the state-of-the-art material for liquid propellant combustion chambers was silicide-coated niobium. However, combustion chamber performance demands have exceeded the capabilities of this material system, requiring development of better materials. The iridium/rhenium combustion chamber, comprising a rhenium structural shell with an iridium inner liner for oxidation protection, represents the current state of the art in high-performance, high temperature, long-life propulsion systems using nitrogen tetroxide/monomethyl hydrazine propellant. However, oxygen/hydrogen (O{sub 2}/H{sub 2}) and new 'green' monopropellants under development to replace hydrazine will be significantly more oxidizing at operating temperature. For these more highly aggressive combustion environments, Ultramet has shown that substantial additional life can be obtained by lining the interior of the combustion chamber with a refractory metal oxide, which functions as a thermal and gas diffusion barrier and provides dramatically increased oxidation resistance. Ultramet has fabricated numerous 22-N (5-lb{sub f}) thrust chambers with this oxide-iridium/rhenium architecture that have been hot-fire tested at NASA Lewis Research Center in O{sub 2}/H{sub 2} propellant at mixture ratios of 6 and 16, with steady-state exterior wall temperatures ranging from 2433 to 2899 K, comprising the most severe temperature and oxidizing conditions ever utilized. Of the seven chambers tested to date, three failed due to facility problems, and two never failed. The best-performing chamber was hot-fired for 13,595 seconds (227 minutes; 3.8 hours) and showed no visible signs of degradation. Additional chambers are being fabricated for future testing.

Fortini, Arthur J.; Tuffias, Robert H. [Ultramet, 12173 Montague St., Pacoima, California 91331 (United States)

1999-01-22

412

Characterization and testing of a new environmental chamber designed for emission aging studies  

NASA Astrophysics Data System (ADS)

A 29 m3 Teflon chamber, designed for aging studies of combustion aerosols, at the University of Eastern Finland is described and characterized. The chamber belongs to a research facility, called Ilmari, where small-scale combustion devices, a dynamometer for vehicle exhaust studies, dilution systems, the chamber, as well as cell and animal exposure devices are side by side under the same roof. The small surface-to-volume ratio of the chamber enables reasonably long experiment times, with particle wall loss rate constants of 0.088, 0.080, 0.045, and 0.040 h-1 for polydisperse, 50, 100, and 200 nm monodisperse aerosols, respectively. The NO2 photolysis rate can be adjusted from zero to 0.62 min-1. The irradiance spectrum is centered at 365 nm and the maximum irradiance, produced by 160 blacklight lamps, is 29.7 W m-2, which corresponds to the UV irradiance in Central Finland at noon on a sunny day in the midsummer. The temperature inside the chamber is uniform and can be kept at 25 ± 1 °C when half of the blacklights are on. The chamber is kept in an overpressure with a moving top frame, which prevents sample dilution and contamination from entering the chamber during an experiment. The functionality of the chamber was tested with oxidation experiments of toluene, resulting in secondary organic aerosol (SOA) yields of 33-44%, depending on the initial conditions, such as the NOx concentration. The highest gaseous oxidation product yields of 14.4-19.5% were detected with ions corresponding to 2-butenedial (m/z 73.029) and 4-oxo-2-pentenal (m/z 99.044). Overall, reasonable yields of SOA and gaseous reaction products, comparable to those obtained in other laboratories, were obtained.

Leskinen, A.; Yli-Pirilä, P.; Kuuspalo, K.; Sippula, O.; Jalava, P.; Hirvonen, M.-R.; Jokiniemi, J.; Virtanen, A.; Komppula, M.; Lehtinen, K. E. J.

2014-06-01

413

21 CFR 884.5225 - Abdominal decompression chamber.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Abdominal decompression chamber. 884.5225 Section...Devices § 884.5225 Abdominal decompression chamber. (a) Identification. An abdominal decompression chamber is a hoodlike device...

2011-04-01

414

21 CFR 884.5225 - Abdominal decompression chamber.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Abdominal decompression chamber. 884.5225 Section...Devices § 884.5225 Abdominal decompression chamber. (a) Identification. An abdominal decompression chamber is a hoodlike device...

2012-04-01

415

21 CFR 884.5225 - Abdominal decompression chamber.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Abdominal decompression chamber. 884.5225 Section...Devices § 884.5225 Abdominal decompression chamber. (a) Identification. An abdominal decompression chamber is a hoodlike device...

2014-04-01

416

21 CFR 884.5225 - Abdominal decompression chamber.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Abdominal decompression chamber. 884.5225 Section...Devices § 884.5225 Abdominal decompression chamber. (a) Identification. An abdominal decompression chamber is a hoodlike device...

2010-04-01

417

21 CFR 884.5225 - Abdominal decompression chamber.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Abdominal decompression chamber. 884.5225 Section...Devices § 884.5225 Abdominal decompression chamber. (a) Identification. An abdominal decompression chamber is a hoodlike device...

2013-04-01

418

21 CFR 880.5450 - Patient care reverse isolation chamber.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Patient care reverse isolation chamber. 880.5450 Section 880...880.5450 Patient care reverse isolation chamber. (a) Identification. A patient care reverse isolation chamber is a device...

2014-04-01

419

21 CFR 880.5450 - Patient care reverse isolation chamber.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Patient care reverse isolation chamber. 880.5450 Section 880...880.5450 Patient care reverse isolation chamber. (a) Identification. A patient care reverse isolation chamber is a device...

2012-04-01

420

21 CFR 880.5450 - Patient care reverse isolation chamber.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Patient care reverse isolation chamber. 880.5450 Section 880...880.5450 Patient care reverse isolation chamber. (a) Identification. A patient care reverse isolation chamber is a device...

2011-04-01

421

21 CFR 880.5450 - Patient care reverse isolation chamber.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Patient care reverse isolation chamber. 880.5450 Section 880...880.5450 Patient care reverse isolation chamber. (a) Identification. A patient care reverse isolation chamber is a device...

2013-04-01

422

21 CFR 880.5450 - Patient care reverse isolation chamber.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Patient care reverse isolation chamber. 880...Therapeutic Devices § 880.5450 Patient care reverse isolation chamber. (a) Identification. A patient care reverse isolation chamber...

2010-04-01

423

Cryogenic optical system development for AEDC's 10V chamber  

NASA Astrophysics Data System (ADS)

The 10V Chamber Test Facility at the Arnold Engineering Development Center (AEDC) is being upgraded to provide a closed-loop capability to assess multi-band electro-optical sensor performance under realistic operational scenarios against evolving threats. This test facility will leverage existing facilities and expertise from several Government agencies including AEDC, Army/AMCOM, and USAF/KHILS to investigate performance issues during ground testing at cryogenic conditions. Radiometrically accurate simulated scenes will be presented to the test article using dual-band infrared point sources, a dual-band infrared emitter array projector, and a visible array projector. Various optical assemblies will be required to project the images from these radiometric source systems onto the sensor aperture. The infrared point sources will be positioned in the XY plane using two-stage linear translators, which must meet stringent spatial coverage and position accuracy requirements to create realistic closed-loop target motion. A large two-axis steering mirror will simulate sensor line of sight movements for the blackbody sources. A high-speed jitter mirror will simulate high frequency image motion for the emitter arrays. These mirror systems must be vibrationally isolated to minimize the jitter induced in other optical elements. Narcissus and ghost image effects will be minimized using appropriate fabrication, shielding, and calibration techniques. A multi-spectral calibration and alignment system will be integrated into the facility to ensure proper radiometric and goniometric operation of the various target sources. The target and optical systems must all meet performance specifications at cryo-vacuum conditions. Code V will be the primary tool used to evaluate wave front error and distortion coating performance for ghosting/polarization/transmission effects, optical manufacturing errors, and energy-on-detector (EOD). Finite element models of the facility will be used to analyze the structural rigidity and dynamics of the components due to the cryogenic environment.

Lowry, Heard S., III; Simpson, William R.; Nicholson, Randy A.; Crosswy, Frank L.; Selman, James D., Jr.

2002-11-01

424

Extremely Low Frequency (ELF) vertical electric field exposure of rats: Irradiation facility  

Microsoft Academic Search

An extremely low frequency (ELF) vertical, electric field irradiation facility consisting of six identical exposure chambers is described. This facility simulates the vertical electric field radiated from the U. S. Navy's proposed ELF Communications System, designed to establish worldwide communication with our submarine fleet. This irradiation facility is designed to study the possible bioeffects of ELF on 96 rats equally

N. S. Matthewson; S. A. Oliva; G. M. Oosta; A. P. Blasco

1977-01-01

425

CHAMBER MUSIC CONCERT Altman, E. Piano  

E-print Network

CHAMBER MUSIC CONCERT Altman, E. Piano Daley, D.J. Piano Foss, S. Piano Konstantopoulos, T. Guitar Pollett, P. Cello Shwartz, A. Guitar Spieksma, F. Piano MUSICAL TALK Themes and variations on ``Ah vous

Shwartz, Adam

426

The Mars Chamber - Duration: 111 seconds.  

NASA Video Gallery

The Mars chamber is a box about the size of a refrigerator that re-creates the temperatures, pressures, and atmosphere of the Martian surface, essentially creating a Mars environment on Earth! Scie...

427

Mini-PROTEAN Multi-Casting Chamber  

E-print Network

ºC for future use. 1.2 Specifications Materials of construction Clamps Glass filled polycarbonate Casting chamber, sealing plate Molded polycarbonate Gasket Silicone tubing Overall size 10 cm x 10 cm x 16

Raizada, Manish N.

428

EFFECT OF DIETHYLHYDROXYLAMINE ON SMOG CHAMBER IRRADIATIONS  

EPA Science Inventory

The addition of diethylhydroxylamine (DEHA) to the urban atmosphere had been suggested as a means of preventing photochemical smog. Smog chamber studies were carried out to investigate the photochemical smog formation characteristics of irradiated hydrocarbon-nitrogen oxides - DE...

429

Developing cloud chambers with high school students  

E-print Network

The result and outcome of the cloud chamber project, which aims to develop a cloud chamber useful for science education is reported in detail. A project includes both three high school students and a teacher as a part of Super Science High School (SSH) program in our school. We develop a dry ice free cloud chamber using salt and ice (or snow). Technical detail of the chamber is presented. We also argue how the project affects student's cognition, motivation, academic skills and behavior. The research project had been done in very similar way to those of professional researchers, i.e., planning research, applying fund, writing a paper and giving a talk in conferences. From interviews with students, we learn that such style of scientific activity is very effective in promoting student's motivation for learning science.

Ishizuka, Ryo; Sato, Shoma; Zeze, Syoji

2013-01-01

430

Formation mechanisms of combustion chamber deposits  

E-print Network

Combustion chamber deposits are found in virtually all internal combustion engines after a few hundred hours of operation. Deposits form on cylinder, piston, and head surfaces that are in contact with fuel-air mixture ...

O'Brien, Christopher J. (Christopher John)

2001-01-01

431

HYLIFE-II reactor chamber design refinements  

SciTech Connect

Mechanical design features of the reactor chamber for the HYLIFE-II inertial confinement fusion power plant are presented. A combination of oscillating and steady, molten salt streams (Li{sub 2}BeF{sub 4}) are used for shielding and blast protection of the chamber walls. The system is designed for a 6 Hz repetition rate. Beam path clearing, between shots, is accomplished with the oscillating flow. The mechanism for generating the oscillating streams is described. A design configuration of the vessel wall allows adequate cooling and provides extra shielding to reduce thermal stresses to tolerable levels. The bottom portion of the reactor chamber is designed to minimize splash back of the high velocity (>12 m/s) salt streams and also recover up to half of the dynamic head. Cost estimates for a 1 GWe and 2 GWe reactor chamber are presented.

House, P.A.

1994-06-01

432

Developing Cloud Chambers with High School Students  

NASA Astrophysics Data System (ADS)

The result and outcome of the cloud chamber project, which aims to develop a cloud chamber useful for science education is reported in detail. A project includes both three high school students and a teacher as a part of Super Science High School (SSH) program in our school. We develop a dry-ice-free cloud chamber using salt and ice (or snow). Technical details of the chamber are described. We also argue how the project have affected student's cognition, motivation, academic skills and behavior. The research project has taken steps of professional researchers, i.e., in planning research, applying fund, writing a paper and giving a talk in conferences. From interviews with students, we have learnt that such style of scientific activity is very effective in promoting student's motivation for learning science.

Ishizuka, Ryo; Tan, Nobuaki; Sato, Shoma; Zeze, Syoji

433

FACILITY DATABASE  

Cancer.gov

January 2008 LASP FACILTY Database Form 5.000 Issue Reporting Form This form is used to report data and/or program related issues regarding the FACILITY database, Supplemental, or the LASP Online Access System. Before submitting this form,

434

Health Facilities  

MedlinePLUS

Health facilities are places that provide health care. They include hospitals, clinics, outpatient care centers, and specialized care centers, such as birthing centers and psychiatric care centers. When you ...

435

FACILITY DATABASE  

Cancer.gov

LASP Administrative Use Only Data Entry Start Date _______________ July 2007 LASP FACILTY Database Form 1.000 FACILITY DATABASE Principal Investigator – Data Entry Requirements This form is used to identify the level of data that each investigator

436

School Facilities.  

ERIC Educational Resources Information Center

Describes the building designs of eight school athletic and recreational facilities, including the educational contexts and design goals. Includes information on architects and designers, construction cost, size, and occupancy date. Also provides photographs. (EV)

Athletic Business, 2002

2002-01-01

437

Numerical simulation of magma chamber dynamics.  

NASA Astrophysics Data System (ADS)

Magma chambers are characterized by periodic arrivals of deep magma batches that give origin to complex patterns of magma convection and mixing, and modify the distribution of physical quantities inside the chamber. We simulate the transient, 2D, multi-component homogeneous dynamics in geometrically complex dyke+chamber systems, by means of GALES, a finite element parallel C++ code solving mass, momentum and energy equations for multi-component homogeneous gas-liquid (± crystals) mixtures in compressible-to-incompressible flow conditions. Code validation analysis includes several cases from the classical engineering literature, corresponding to a variety of subsonic to supersonic gas-liquid flow regimes (see http://www.pi.ingv.it/~longo/gales/gales.html). The model allows specification of the composition of the different magmas in the domain, in terms of ten major oxides plus the two volatile species H2O and CO2. Gas-liquid thermodynamics are modeled by using the compositional dependent, non-ideal model in Papale et al. (Chem.. Geol., 2006). Magma properties are defined in terms of local pressure, temperature, and composition including volatiles. Several applications are performed within domains characterized by the presence of one or more magma chambers and one or more dykes, with different geometries and characteristic size from hundreds of m to several km. In most simulations an initial compositional interface is placed at the top of a feeding dyke, or at larger depth, with the deeper magma having a lower density as a consequence of larger volatile content. The numerical results show complex patterns of magma refilling in the chamber, with alternating phases of magma ingression and magma sinking from the chamber into the feeding dyke. Intense mixing takes place in feeding dykes, so that the new magma entering the chamber is always a mixture of the deep and the initially resident magma. Buoyant plume rise occurs through the formation of complex convective patterns, giving origin to a density-stratified magma chamber.

Longo, Antonella; Papale, Paolo; Montagna, Chiara Paola; Vassalli, Melissa; Giudice, Salvatore; Cassioli, Andrea

2010-05-01

438

Combustion chamber layout for modern Otto engines  

SciTech Connect

Since the most efficient way to improve fuel economy in the part-load range is to increase the compression ratio, emphasis is placed on combustion chambers allowing high compression ratios combined with low octane requirements. According to Porsche experience, many demands can be met in the simplest manner by locating the combustion chamber in the piston crown. This configuration offers various advantages over its counterpart installed in the cylinder head. 24 refs.

Gruden, D.O.

1981-10-01

439

Cloud chamber visualization of primary cosmic rays  

SciTech Connect

From 1948 until 1963, cloud chambers were carried to the top of the atmosphere by balloons. From these flights, which were begun by Edward P. Ney at the University of Minnesota, came the following results: discovery of heavy cosmic ray nuclei, development of scintillation and cherenkov detectors, discovery of cosmic ray electrons, and studies of solar proton events. The history of that era is illustrated here by cloud chamber photographs of primary cosmic rays.

Earl, James A. [Department of Astronomy, University of Maryland, College Park MD (United States)

2013-02-07

440

V-particles and the cloud chamber  

Microsoft Academic Search

In Table I are shown some rough details of some of the main cloud chambers being used in different parts of the world for the study of V-events by the method of the counter controlled cloud chamber. Between one and two thousand neutral and charged V-events must have already been photographed since their accidental discovery by ROCm~ST~R and BUTLFA~ in

P. M. S. Blackett

1954-01-01

441

Engine Knock and Combustion Chamber Form  

NASA Technical Reports Server (NTRS)

The present report is confined to the effect of the combustion chamber shape on engine knock from three angles, namely: 1) The uniformity of flame-front movement as affected by chamber design and position of the spark plug; 2) The speed of advance of the flame as affected by turbulence and vibrations; 3) The reaction processes in the residual charge as affected by the walls.

Zinner, Karl

1939-01-01

442

Assessing the Fidelity of COTS 802.11 Sniffers Pablo Serrano  

E-print Network

in this paper) by running controlled experiments inside an anechoic chamber and analyzing the similarities) of four different passive wireless packet capture devices (sniffers) in an anechoic chamber, in which of the anechoic chamber enables the assessment of fidelity in four ways: i) It provides an interference

Kurose, Jim

443

575ELECTRONICS LETTERS 25th April 2013 Vol.49 No.9doi: 10.1049/el.2013.1241 FURTHER READING  

E-print Network

reflection of a realistic wireless propagation environment inside an anechoic chamber. One of the next stages for use in multi-probe anechoic chamber-based testing, developed and implemented by collaborating for MIMO devices using an anechoic chamber were first introduced in CTIA, COST action 2100 and 3GPP in 2009

Berning, Torsten

444

This work is licensed under a Creative Commons Attribution 3.0 License. For more information, see http://creativecommons.org/licenses/by/3.0/. This article has been accepted for publication in a future issue of this journal, but has not been fully edited.  

E-print Network

, where a multi-probe anechoic chamber based method is a promising candidate. Setting up a multi results. There are three main types of OTA test methods for MIMO devices: multi-probe anechoic chamber method; and the cost of the setup is the main issue with the multi-probe anechoic chamber-based method [1

Berning, Torsten

445

ccsd-00014092,version1-18Nov2005 Active control of scattered acoustic radiation  

E-print Network

a feasible experiment in an anechoic chamber with a limited number of control sources. Eventually a real of the noise scattered in an anechoic chamber by a rigid parallelepiped. Active control of scattered noise. Cancellation of the reflections from the walls of anechoic chambers at low frequency is another potential

Paris-Sud XI, Université de

446

Cyclic fatigue analysis of rocket thrust chambers. Volume 1: OFHC copper chamber low cycle fatigue  

NASA Technical Reports Server (NTRS)

A three-dimensional finite element elasto-plastic strain analysis was performed for the throat section of a regeneratively cooled rocket combustion chamber. The analysis employed the RETSCP finite element computer program. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the chamber operating cycle. The analysis was performed for chamber configuration and operating conditions corresponding to a hydrogen-oxygen combustion chamber which was fatigue tested to failure. The computed strain range at typical chamber operating conditions was used in conjunction with oxygen-free, high-conductivity (OHFC) copper isothermal fatigue test data to predict chamber low-cycle fatigue life.

Miller, R. W.

1974-01-01

447

Calibration of IR test chambers with the missile defense transfer radiometer  

NASA Astrophysics Data System (ADS)

The Missile Defense Transfer Radiometer (MDXR) is designed to calibrate infrared collimated and flood sources over the fW/cm2 to W/cm2 power range from 3 ?m to 28? m in wavelength. The MDXR operates in three different modes: as a filter radiometer, a Fourier-transform spectrometer (FTS)-based spectroradiometer, and as an absolute cryogenic radiometer (ACR). Since 2010, the MDXR has made measurements of the collimated infrared irradiance at the output port of seven different infrared test chambers at several facilities. We present a selection of results from these calibration efforts compared to signal predictions from the respective chamber models for the three different MDXR calibration modes. We also compare the results to previous measurements made of the same chambers with a legacy transfer radiometer, the NIST BXR. In general, the results are found to agree within their combined uncertainties, with the MDXR having 30 % lower uncertainty and greater spectral coverage.

Kaplan, Simon G.; Woods, Solomon I.; Carter, Adriaan C.; Jung, Timothy M.

2013-05-01

448

Stability of A-150 plastic ionization chamber response over a ~30 year period  

SciTech Connect

At the NIU Institute for Neutron Therapy at Fermilab, the clinical tissue-equivalent ionization chamber response is measured every treatment day using a cesium source that was configured to match readings obtained at the National Bureau of Standards. Daily measurements are performed in air using the air-to-tissue dose conversion factors given in AAPM Report no. 7. The measured exposure calibration factors have been tabulated and graphed as a function of time from 1978 to present. For A-150 plastic ionization chambers, these factors exhibit a sinusoidal variation with a period of approximately one year and amplitude of {+-} 1%. This variation, attributable to the hygroscopic nature of A-150 plastic, is correlated with the relative humidity of the facility, and is greater than the humidity corrections for gas described in the literature. Our data suggest that chamber calibration should be performed at least weekly to accommodate these variations.

Kroc, Thomas K.; Lennox, Arlene J.; /Fermilab

2007-08-01

449

Aerospace test facilities at NASA LERC Plumbrook  

NASA Astrophysics Data System (ADS)

An overview of the facilities and research being conducted at LeRC's Plumbrook field station is given. The video highlights four main structures and explains their uses. The Space Power Facility is the worlds largest space environment simulation chamber, where spacebound hardware is tested in simulations of the vacuum and extreme heat and cold of the space plasma environment. This facility was used to prepare Atlas 1 rockets to ferry CRRES into orbit; it will also be used to test space nuclear electric power generation systems. The Spacecraft Propulsion Research Facility allows rocket vehicles to be hot fired in a simulated space environment. In the Cryogenic Propellant Tank Facility, researchers are developing technology for storing and transferring liquid hydrogen in space. There is also a Hypersonic Wind Tunnel which can perform flow tests with winds up to Mach 7.

1992-10-01

450

Development of sputtered techniques for thrust chambers  

NASA Technical Reports Server (NTRS)

Techniques and materials were developed and evaluated for the fabrication and coating of advanced, long life, regeneratively cooled thrust chambers. Materials were analyzed as fillers for sputter application of OFHC copper as a closeout layer to channeled inner structures; of the materials evaluated, aluminum was found to provide the highest bond strength and to be the most desirable for chamber fabrication. The structures and properties were investigated of thick sputtered OFHC copper, 0.15 Zr-Cu, Al2O3,-Cu, and SiC-Cu. Layered structures of OFHC copper and 0.15 Zr-Cu were investigated as means of improving chamber inner wall fatigue life. The evaluation of sputtered Ti-5Al-2.5Sn, NASA IIb-11, aluminum and Al2O3-Al alloys as high strength chamber outer jackets was performed. Techniques for refurbishing degraded thrust chambers with OFHC copper and coating thrust chambers with protective ZrO2 and graded ZrO2-copper thermal barrier coatings were developed.

Mullaly, J. R.; Hecht, R. J.; Schmid, T. E.; Torrey, C. T.

1975-01-01

451

Expandable Purge Chambers Would Protect Cryogenic Fittings  

NASA Technical Reports Server (NTRS)

Expandable ice-prevention and cleanliness-preservation (EIP-CP) chambers have been proposed to prevent the accumulation of ice or airborne particles on quick-disconnect (QD) fittings, or on ducts or tubes that contain cryogenic fluids. In the original application for which the EIP-CP chambers were conceived, there is a requirement to be able to disconnect and reconnect the QD fittings in rapid succession. If ice were to form on the fittings by condensation and freezing of airborne water vapor on the cold fitting surfaces, the ice could interfere with proper mating of the fittings, making it necessary to wait an unacceptably long time for the ice to thaw before attempting reconnection. By keeping water vapor away from the cold fitting surfaces, the EIP-CP chambers would prevent accumulation of ice, preserving the ability to reconnect as soon as required. Basically, the role of an EIP-CP chamber would be to serve as an enclosure for a flow of dry nitrogen gas that would keep ambient air away from QD cryogenic fittings. An EIP-CP chamber would be an inflatable device made of a fabriclike material. The chamber would be attached to an umbilical plate holding a cryogenic QD fitting.

Townsend, Ivan I., III

2004-01-01

452

Chamber for Growing and Observing Fungi  

NASA Technical Reports Server (NTRS)

A chamber has been designed to enable growth and observation of microcolonies of fungi in isolation from the external environment. Unlike prior fungus-growing apparatuses, this chamber makes it possible to examine a fungus culture without disrupting it. Partly resembling a small picture frame, the chamber includes a metal plate having a rectangular through-thethickness opening with recesses for a top and a bottom cover glass, an inlet for air, and an inlet for water. The bottom cover glass is put in place and held there by clips, then a block of nutrient medium and a moisture pad are placed in the opening. The block is inoculated, then the top cover glass is put in place and held there by clips. Once growth is evident, the chamber can be sealed with tape. Little (if any) water evaporates past the edges of the cover glasses, and, hence there is little (if any) need to add water. A microscope can be used to observe the culture through either cover glass. Because the culture is sealed in the chamber, it is safe to examine the culture without risking contamination. The chamber can be sterilized and reused.

Pierson, Duane L.; Molina, Thomas C.

2005-01-01

453

High-pressure promoted combustion chamber  

NASA Technical Reports Server (NTRS)

In the preferred embodiment of the promoted combusiton chamber disclosed herein, a thick-walled tubular body that is capable of withstanding extreme pressures is arranged with removable upper and lower end closures to provide access to the chamber for dependently supporting a test sample of a material being evaluated in the chamber. To facilitate the real-time analysis of a test sample, several pressure-tight viewing ports capable of withstanding the simulated environmental conditions are arranged in the walls of the tubular body for observing the test sample during the course of the test. A replaceable heat-resistant tubular member and replaceable flame-resistant internal liners are arranged to be fitted inside of the chamber for protecting the interior wall surfaces of the combustion chamber during the evaluation tests. Inlet and outlet ports are provided for admitting high-pressure gases into the chamber as needed for performing dynamic analyses of the test sample during the course of an evaluation test.

Rucker, Michelle A. (inventor); Stoltzfus, Joel M. (inventor)

1991-01-01

454

Focal Point Inside the Vacuum Chamber for Solar Thermal Propulsion  

NASA Technical Reports Server (NTRS)

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. The 20- by 24-ft heliostat mirror (not shown in this photograph) has dual-axis control that keeps a reflection of the sunlight on an 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. This photograph is a close-up view of a 4-in focal point inside the vacuum chamber at the MSFC Solar Thermal Propulsion Test facility. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

1999-01-01

455

Motor Controls for the NIFFTE Time Projection Chamber Positioning Stand  

NASA Astrophysics Data System (ADS)

The next generation nuclear power plants will be more efficient and produce smaller amounts of radioactive waste. Design of these new reactors is limited partially by the lack of precise neutron induced fission cross sections at certain incident neutron energies of several isotopes. In order to reduce the uncertainty of the cross sections to less than 1 percent, a Time Projection Chamber (TPC) was built by the Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) collaboration. These improvements in precision will be possible due to the TPC's ability for a full 3-D reconstruction of the fission fragment tracks. The NIFFTE TPC will be installed at Los Alamos National Lab's LANSCE facility. Thin targets will be mounted in the center of the TPC in a pressurized hydrogen gas chamber so that both hemispheres of the reaction will be covered. In this work we will discuss the control of the stepper motors that drive the positioning table of the TPC, which has all of its readout electronics attached, to be lined up with the beam. This includes both the controlling software and its graphical interface to the MIDAS online data acquisition system.

Pamplin, Daniel; Pickle, Nathan

2010-11-01

456

Developing a fast ionization chamber for transfer reaction studies  

NASA Astrophysics Data System (ADS)

Detection of beam and beam like recoils at far forward angles is often critical for radioactive beam measurements in inverse kinematics. Gas-filled ionization chambers are well suited for these applications, since they have moderately good energy resolution and can take prolonged exposure to beam compared to fragile semiconductor detectors. Conventional ion counters using a Frisch grid, however, have slow response times because the ionized electrons must travel long distances to the anodes. To reduce response times, a fast ion counter using a tilted window and tilted electrodes was developed and tested at ORNL's Holifield Radioactive Ion Beam Facility, modified from an original design by Kimura et al. [1]. The maximum counting rate and energy resolution, along with future plans for using the new ion counter, will be presented. [4pt] [1] K. Kimura et al., Nucl. Inst. Meth. Phys. Res. A 538, 608 (2005).

Chae, K. Y.; Bardayan, D. W.; Smith, M. S.; Schmitt, K. T.; Ahn, S. H.; Peters, W. A.; Strauss, S.

2011-10-01

457

Team Huddle Before Lifting Phoenix into Test Chamber  

NASA Technical Reports Server (NTRS)

Spacecraft specialists huddle to discuss the critical lift of NASA's Phoenix Mars Lander into a thermal vacuum chamber.

In December 2006, the spacecraft was in a cruise configuration prior to going into environmental testing at a Lockheed Martin Space Systems facility near Denver. At all stages of assembly and testing, the spacecraft is handled with extreme care and refinement.

The Phoenix mission is led by Principal Investigator Peter H. Smith of the University of Arizona, Tucson, with project management at NASA's Jet Propulsion Laboratory and development partnership with Lockheed Martin Space Systems. International contributions for Phoenix are provided by the Canadian Space Agency, the University of Neuchatel (Switzerland), the University of Copenhagen, and the Max Planck Institute in Germany. JPL is a division of the California Institute of Technology in Pasadena.

2007-01-01

458

Extremely low frequency (elf) vertical electric field exposure of rats: irradiation facility. Final report  

Microsoft Academic Search

An extremely low frequency (ELF) vertical, electric field irradiation facility consisting of six identical exposure chambers for biological research is described. Each exposure chamber can be independently operated up to field strengths of 1000 V\\/m (RMS) at any sinusoidal ELF frequency. At 45 Hz, the frequency chosen for this research, chamber cross-talk is less than -60 dB and the vertical

N. S. Mathewson; S. A. Oliva; G. M. Oosta; A. P. Blasco

1977-01-01

459

Simulation, design, and construction of a 137Cs irradiation facility.  

PubMed

Regulatory entities require that for any radiation facility the surrounding areas must be restricted unless the dose equivalent is less than 0.02 mSv in any one hour. Two Monte Carlo radiation transport simulation codes, MCNP5 and Mercurad, were used to design a facility to shield a 3.48 x 10(5) MBq 137Cs irradiator that meets these requirements. Simulations showed that the dose equivalent rates were below the legal limit for unrestricted access and the facility was constructed using available concrete block and student labor to minimize costs. To verify the accuracy of the Monte Carlo radiation transport codes, an ion chamber was used to characterize the facility. Ion chamber measurements in the actual, as-built irradiation facility showed that the Monte Carlo codes, MCNP5 and Mercurad, agreed by a factor of better than 6% and better than 11%, respectively. PMID:17440327

Studenski, Matthew T; Haverland, Nathan P; Kearfott, Kimberlee J

2007-05-01

460

Centrifuge facility conceptual system study. Volume 2: Facility systems and study summary  

NASA Technical Reports Server (NTRS)

The Centrifuge Facility is a major element of the biological research facility for the implementation of NASA's Life Science Research Program on Space Station Freedom using nonhuman species (small primates, rodents, plants, insects, cell tissues, etc.). The Centrifuge Facility consists of a variable gravity Centrifuge to provide artificial gravity up to 2 earth G's' a Holding System to maintain specimens at microgravity levels, a Glovebox, and a Service Unit for servicing specimen chambers. The following subject areas are covered: (1) Holding System; (2) Centrifuge System; (3) Glovebox System; (4) Service System; and (5) system study summary.

Synnestvedt, Robert (editor); Blair, Patricia; Cartledge, Alan; Garces-Porcile, Jorge; Garin, Vladimir; Guerrero, Mike; Haddeland, Peter; Horkachuck, Mike; Kuebler, Ulrich; Nguyen, Frank

1991-01-01

461

THE NOAA/EPA FLUID MODELING FACILITY'S CONTRIBUTIONS TO THE UNDERSTANDING OF THE ATMOSPHERIC DISPERSION  

EPA Science Inventory

Over the past thirty years, scientists at the Environmental Protection Agency's (EPA) Fluid Modeling Facility (FMF) have conducted laboratory studies of fluid flow and pollutant dispersion within three distinct experimental chambers: a meteorological wind tunnel, a water-channel ...

462

Characteristics of a delay-line readout in a cylindrical drift chamber system  

NASA Astrophysics Data System (ADS)

This paper reports on the design, construction, and operational characteristics of a delay-line readout implemented on the cathode foils of a cylindrical drift chamber system. The readout was used to determine the position of an event along the length of the 1.74 m drift wires in the MEGA detectors used at the Los Alamos Meson Physics Facility. The performance of the system is interpreted by comparison to a PSPICE simulation, and to simple analytical models.

Barber, R.; Ahmed, M. W.; Dzemidzic, M.; Empl, A.; Hungerford, E. V.; Lan, K. J.; Wilson, J.; Cooper, M. D.; Gagliardi, C. A.; Haim, D.; Kim, G. J.; Koetke, D. D.; Tribble, R. E.; Van Ausdeln, L. A.

2002-03-01

463

Infrared transfer radiometer for broadband and spectral calibration of space chambers  

Microsoft Academic Search

The Low-Background Infrared (LBIR) facility at NIST has recently completed construction of an infrared transfer radiometer with an integrated cryogenic Fourier transform spectrometer (Cryo-FTS). This mobile system can be deployed to customer sites for broadband and spectral calibrations of space chambers and low-background HWIL testbeds. The Missile Defense Transfer Radiometer (MDXR) has many of the capabilities of a complete IR

Timothy M. Jung; Adriaan C. Carter; Solomon I. Woods; Simon G. Kaplan; Raju U. Datla

2010-01-01

464

Performance Of A Liquid Argon Time Projection Chamber Exposed To The WANF Neutrino Beam  

E-print Network

We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct low multiplicity neutrino interactions.

F. Arneodo et al.

2006-09-25

465

Outdoor smog chamber experiments to test photochemical models. Final report May 78-May 81  

SciTech Connect

The smog chamber facility of the University of North Carolina was used in a study to provide experimental data for developing and testing kinetic mechanisms of photochemical smog formation. The smog chamber, located outdoors in rural North Carolina, is an A-frame structure covered with Teflon film. Because the chamber is partitioned into two sections, each with a volume of 156 cu m, two experiments can be conducted simultaneously. The dual chamber is operated under natural conditions of solar radiation, temperature, and relative humidity. In this study, 115 dual all-day experiments were conducted using NOx and a variety of organic species. The organic compounds investigated included various paraffins, olefins, aromatics and oxygenates, both singly and in mixtures of two or more components. In this report the data collected over the three-year period of the study are described. The experimental procedures and analytical methods used in this study and the limitations and uncertainties of the data are discussed. Guidance for modeling of the data is also given, including a detailed discussion of how to estimate photolytic rate constants from the available UV and total solar radiation data and how to treat such chamber artifacts as dilution, wall sources and losses of pollutants, and reactivity of the background air.

Feffries, H.E.; Kamens, R.M.; Sexron, K.G.; Gerhardt, A.A.

1982-04-01

466

Measurements of a 1/4-scale model of an explosives firing chamber  

SciTech Connect

In anticipation of increasingly stringent environmental regulations, Lawrence Livermore National Laboratory (LLNL) proposes to construct a 60-kg firing chamber to provide blast-effects containment for most of its open-air, high-explosive, firing operations. Even though these operations are within current environmental limits, containment of the blast effects and hazardous debris will further drastically reduce emissions to the environment and minimize the generated hazardous waste. The major design consideration of such a chamber is its overall structural dynamic response in terms of long-term containment of all blast effects from repeated internal detonations of high explosives. Another concern is how much other portions of the facility outside the firing chamber must be hardened to ensure personnel protection in the event of an accidental detonation while the chamber door is open. To assess these concerns, a 1/4-scale replica model of the planned contained firing chamber was designed, constructed, and tested with scaled explosive charges ranging from 25 to 125% of the operational explosives limit of 60 kg. From 16 detonations of high explosives, 880 resulting strains, blast pressures, and temperatures within the model were measured to provide information for the final design. Factors of safety for dynamic yield of the firing chamber structure were calculated and compared to the design criterion of totally elastic response. The rectangular, reinforced-concrete chamber model exhibited a lightly damped vibrational response that placed the structure in alternating cycles of tension and compression. During compression, both the reinforcing steel and the concrete remained elastic.

Pastrnak, J.W.; Baker, C.F.; Simmons, L.F.

1995-01-27

467

Preliminary studies of a new monitor ionization chamber  

Microsoft Academic Search

A new monitor ionization chamber was developed at Instituto de Pesquisas Energéticas e Nucleares (IPEN) in order to monitor X-ray beams. The main difference of this monitor ionization chamber in relation to other monitor chambers is its geometry, which consists of a ring-shaped sensitive volume. Because of this geometry, the monitor chamber has a central hole through which the direct

Maíra T. Yoshizumi; Vitor Vivolo; Linda V. E. Caldas

2010-01-01

468

Resources at Princeton U. Relevant to BABAR Drift Chamber  

E-print Network

emphasized cosmic ray V ­particles, observed in cloud chambers triggered by Geiger tubes on Mt. Evans, COResources at Princeton U. Relevant to BABAR Drift Chamber Construction K.T. McDonald Princeton U spark chamber (unstable), Keuffel, '50. -- Scintillating fiber, Reynolds, '57. -- Scintillating chamber

McDonald, Kirk

469

Resources at Princeton U. Relevant to BABAR Drift Chamber  

E-print Network

emphasized cosmic ray V - particles, observed in cloud chambers triggered by Geiger tubes on Mt. Evans, COResources at Princeton U. Relevant to BABAR Drift Chamber Construction K.T. McDonald Princeton U chamber (unstable), Keuffel, '50. ­ Scintillating fiber, Reynolds, '57. ­ Scintillating chamber

McDonald, Kirk

470

The construction of the KLOE drift chamber: Present status KLOE Drift Chamber Group  

NASA Astrophysics Data System (ADS)

The status of the construction of the KLOE Drift Chamber is reviewed. With its 4 m diameter, it will be the biggest drift chamber ever built. The stringing of 52 000 wires is a titanic effort: details are given about the semiautomatic system, the quality tests on wires and the monitoring of end-plates deformations.

Valente, Paolo; Andryakov, A.; Antonelli, A.; Baldini-Ferroli, R.; Bencivenni, G.; Bucci, L.; Calcaterra, A.; Campana, P. L.; Dell'Agnello, S.; de Sangro, R.; De Simone, P.; Felici, G.; Finocchiaro, G.; Forti, C.; Moccia, S.; Passalacqua, L.; Patera, V.; Piccolo, M.; Kulikov, V.; Nedosekin, A.; Cataldi, G.; Denig, A.; Kluge, W.; Von Hagel, U.; Weseler, S.; Elia, V.; Golovatyuk, V.; Gorini, E.; Grancagnolo, F.; Panareo, M.; Primavera, M.; Spagnolo, S.; De Lucia, E.; Lacava, F.; Luisi, C.; Picca, D.; Pontecorvo, L.; Messi, R.; Paoluzi, L.; Valente, P.; Bacci, C.; Ceradini, F.

1998-02-01

471

Fusion Engineering and Design 81 (2006) 16271638 Progress towards realization of a laser IFE solid wall chamber  

E-print Network

of the armor thermo-mechanical behavior in facilities utilizing ion, X-rays and laser sources to simulate IFE. Sharafatg, L. Sneadh, the HAPL Team a Mechanical and Aerospace Department and Center for Energy Research behavior in tungsten. This paper summarizes the HAPL chamber activities. The first wall/armor configuration

Raffray, A. René

2006-01-01

472

NSTAR Extended Life Test Discharge Chamber Flake Analysis  

NASA Technical Reports Server (NTRS)

The Extended Life Test (ELT) of the NASA Solar Electric Propulsion Technology Readiness (NSTAR) ion thruster was concluded after 30,352 hours of operation. The ELT was conducted using the Deep Space 1 (DS1) back-up flight engine, a 30 cm diameter xenon ion thruster. Post-test inspection of the ELT engine revealed numerous contaminant flakes distributed over the bottom of the cylindrical section of the anode within the discharge chamber (DC). Extensive analyses were conducted to determine the source of the particles, which is critical to the understanding of degradation mechanisms of long life ion thruster operation. Analyses included: optical microscopy (OM) and particle length histograms, field emission scanning electron microscopy (FESEM) combined with energy dispersive spectroscopy (EDS), and atomic oxygen plasma exposure tests. Analyses of the particles indicate that the majority of the DC flakes consist of a layered structure, typically with either two or three layers. The flakes comprising two layers were typically found to have a molybdenum-rich (Mo-rich) layer on one side and a carbon-rich (C-rich) layer on the other side. The flakes comprising three layers were found to be sandwich-like structures with Mo-rich exterior layers and a C-rich interior layer. The presence of the C-rich layers indicates that these particles were produced by sputter deposition build-up on a surface external to the discharge chamber from ion sputter erosion of the graphite target in the test chamber. This contaminant layer became thick enough that particles spalled off, and then were electro-statically attracted into the ion thruster interior, where they were coated with Mo from internal sputter erosion of the screen grid and cathode components. Atomic oxygen tests provided evidence that the DC chamber flakes are composed of a significant fraction of carbon. Particle size histograms further indicated that the source of the particles was spalling of carbon flakes from downstream surfaces. Analyses of flakes taken from the downstream surface of the accelerator grid provided additional supportive information. The production of the downstream carbon flakes, and hence the potential problems associated with the flake particles in the ELT ion thruster engine is a facility induced effect and would not occur in the space environment.

deGroh, Kim K.; Banks, Bruce A.; Karniotis, Christina A.

2005-01-01

473

High temperature thrust chamber for spacecraft  

NASA Technical Reports Server (NTRS)

A high temperature thrust chamber for spacecraft (20) is provided herein. The high temperature thrust chamber comprises a hollow body member (12) having an outer surface and an internal surface (16) defining the high temperature chamber (10). The body member (12) is made substantially of rhenium. An alloy (18) consisting of iridium and at least alloying metal selected of the group consisting of rhodium, platinum and palladium is deposited on at least a portion of the internal surface (16) of the body member (12). The iridium and the alloying metal are electrodeposited onto the body member (12). A HIP cycle is performed upon the body member (12) to cause the coating of iridium and the alloying metal to form the alloy (18) which protects the body member (12) from oxidation.

Chazen, Melvin L. (Inventor); Mueller, Thomas J. (Inventor); Kruse, William D. (Inventor)

1998-01-01

474

Double-chambered right ventricle: a review.  

PubMed

A double-chambered right ventricle is a rare heart defect in which the right ventricle is separated into a high-pressure proximal and low-pressure distal chamber. This defect is considered to be congenital and typically presents in infancy or childhood but has been reported to present rarely in adults. It can be caused by the presence of anomalous muscle tissue, hypertrophy of the endogenous trabecular bands, or an aberrant moderator band; all of which will typically result in progressive obstruction of the outflow tract. In this paper, we will discuss the general anatomy of the right ventricle, the relevant embryology of the heart, and the presentation, diagnosis, and treatment of a double-chambered right ventricle. PMID:23701985

Loukas, Marios; Housman, Brian; Blaak, Christa; Kralovic, Sarah; Tubbs, R Shane; Anderson, Robert H

2013-01-01

475

Facilities Management.  

ERIC Educational Resources Information Center

Presents responses from Matt McGovern, "School Planning and Management's" Maintenance and Operations columnist, on the issue of school facility maintenance. McGovern does not believe schools will ever likely meet acceptable levels of maintenance, nor use infrared thermography for assessing roofs, outsource all maintenance work, nor find a pressing…

Bete, Tim, Ed.

1998-01-01

476

Simulation of BaBar Drift Chamber  

SciTech Connect

The BaBar drift chamber (DCH) is used to measure the properties of charged particles created from e{sup +}e{sup -} collisions in the PEP-II asymmetric-energy storage rings by making precise measurements of position, momentum and ionization energy loss (dE/dx). In October of 2005, the PEP-II storage rings operated with a luminosity of 10 x 10{sup 33} cm{sup -2}s{sup -1}; the goal for 2007 is a luminosity of 20 x 10{sup 33} cm{sup -2}s{sup -1}, which will increase the readout dead time, causing uncertainty in drift chamber measurements to become more significant in physics results. The research described in this paper aims to reduce position and dE/dx uncertainties by improving our understanding of the BaBar drift chamber performance. A simulation program--called GARFIELD--is used to model the behavior of the drift chamber with adjustable parameters such as gas mixture, wire diameter, voltage, and magnetic field. By exploring the simulation options offered in GARFIELD, we successfully produced a simulation model of the BaBar drift chamber. We compared the time-to-distance calibration from BaBar to that calculated by GARFIELD to validate our model as well as check for discrepancies between the simulated and calibrated time-to-distance functions, and found that for a 0{sup o} entrance angle there is a very good match between calibrations, but at an entrance angle of 90{sup o} the calibration breaks down. Using this model, we also systematically varied the gas mixture to find one that would optimize chamber operation, which showed that the gas mixture of 80:20 Helium:isobutane is a good operating point, though more calculations need to be done to confirm that it is the optimal mixture.

Anderson, Rachel; /Wisconsin U., Eau Claire /SLAC

2006-09-27

477

CCN comparisons of static diffusion chambers  

NASA Technical Reports Server (NTRS)

Nine CCN counters of the static diffusion (SDC) type were compared with one another and with continuous flow diffusion (CFD) chambers. The nine SDCs showed a considerable amount of variation, largely attributable to newness and/or lack of prior calibration of some units. The five more consistent instruments agreed quite well, to within at least 20 percent of the NRL mobility analyzer and to within 10 percent at 1 percent supersaturation. There was satisfactory agreement between the more reliable SDC and CFD chambers.

Jiusto, J. E.; Ruskin, R. E.; Gagin, A.

1981-01-01

478

Advanced technology application for combustion chamber concepts  

NASA Technical Reports Server (NTRS)

NASA-Marshall is engaged in the development of an Advanced Main Combustion Chamber under the aegis of the Earth-to-Orbit Propulsion Technology Program. AMCC is to be a robust and highly reliable combustion-chamber prototype costing one-third as much as current designs of comparable performance; it will be associated with a reduction of fabrication time by one-half. Attention is presently given to the three component-manufacturing processes used: single-piece investment casting for the structural jacket and manifolds; vacuum plasma spraying, for the combustion liner, and an alternative, platelet-compounded liner.

Tygielski, Kathy S.

1992-01-01

479

CF{sub 4}/isobutane drift chamber  

SciTech Connect

Investigations of a drift chamber with a square 6x6-mm cell filled with a mixture of 80% CF{sub 4} and 20% isobutane are discussed. Experiments have been performed under a beam of electron, muons, and pions with a momentum of 64 MeV/c at the TRIUMF accelerator (Canada). The coordinate resolution of the chamber with respect to relativistic particles {sigma}{approx}120 {mu}m and the total collection time of ionization electrons (dead time) is {approx} 35 nsec. The probability of {sigma}-electron generation in the gas mixture has been determined.

Abadzhev, V.S.; Dzhilkibaev, R.M.; Plisko, I.A. [Institute for Nuclear Research, Moscow (Russian Federation)] [and others

1995-07-01

480

Sealed Plant-Growth Chamber For Clinostat  

NASA Technical Reports Server (NTRS)

Laboratory chamber for growing plants used to measure photosynthesis and respiration in simulated microgravity. Holds plant specimens while rotated on clinostat, see article, "Clinostat Delivers Power To Plant-Growth Cabinets" (KSC-11537). Provides way of comparing gas-exchange rates of plants rotated horizontally on clinostat with those of stationary or vertically rotated plants. Gas extracted for analysis without stopping clinostat. Chamber includes potlike base and cylindrical cover, both made of transparent acrylic pipe. Gasket forms seal between cover and bottom plate of base. Cover bolted to pot baseplate, which in turn bolted to clinostat.

Brown, Christopher S.; Dreschel, Thomas W.

1993-01-01

481

Secondary organic aerosol formation from gasoline vehicle emissions in a new mobile environmental reaction chamber  

NASA Astrophysics Data System (ADS)

We present a new mobile environmental reaction chamber for the simulation of the atmospheric aging of aerosols from different emissions sources without limitation from the instruments or facilities available at any single site. The chamber can be mounted on a trailer for transport to host facilities or for mobile measurements. Photochemistry is simulated using a set of 40 UV lights (total power 4 KW). Characterisation of the emission spectrum of these lights shows that atmospheric photochemistry can be accurately simulated over a range of temperatures from -7-25 °C. A photolysis rate of NO2, JNO2, of (8.0 ± 0.7) × 10-3 molecules cm-3 s-1 was determined at 25 °C. Further, we present the first application of the mobile chamber and demonstrate its utility by quantifying primary organic aerosol (POA) emission and secondary organic aerosol (SOA) production from a Euro 5 light duty gasoline vehicle. Exhaust emissions were sampled during the New European Driving Cycle (NEDC), the standard driving cycle for European regulatory purposes, and injected into the chamber. The relative concentrations of oxides of nitrogen (NOx) and total hydrocarbon (THC) during the aging of emissions inside the chamber were controlled using an injection system developed as a part of the new mobile chamber set up. Total OA (POA + SOA) emission factors of (370 ± 18) × 10-3 g kg-1 fuel, or (14.6 ± 0.8) × 10-3 g km-1, after aging, were calculated from concentrations measured inside the smog chamber during two experiments. The average SOA/POA ratio for the two experiments was 15.1, a much larger increase than has previously been seen for diesel vehicles, where smog chamber studies have found SOA/POA ratios of 1.3-1.7. Due to this SOA formation, carbonaceous particulate matter (PM) emissions from a gasoline vehicle may approach those of a diesel vehicle of the same class. Furthermore, with the advent of emission controls requiring the use of diesel particle filters, gasoline vehicle emissions could become a far larger source of ambient PM than diesel vehicles. Therefore this large increase in the PM mass of gasoline vehicle aerosol emissions due to SOA formation has significant implications for our understanding of the contribution of on-road vehicles to ambient aerosols and merits further study.

Platt, S. M.; El Haddad, I.; Zardini, A. A.; Clairotte, M.; Astorga, C.; Wolf, R.; Slowik, J. G.; Temime-Roussel, B.; Marchand, N.; Ježek, I.; Drinovec, L.; Mo?nik, G.; Möhler, O.; Richter, R.; Barmet, P.; Bianchi, F.; Baltensperger, U.; Prévôt, A. S. H.

2012-10-01

482

Thermistors Used in Climatic Chamber at High Temperature and Humidity  

NASA Astrophysics Data System (ADS)

In 2011, VSL initiated the development of a facility for a relative humidity between and for calibrating high-temperature relative humidity sensors at pressures other than atmospheric. The setup for calculating the relative humidity uses the dew-point temperature, measured by a chilled mirror hygrometer, and the temperature distribution in the chamber, measured by a series of thermistors. This paper describes the results of thermal tests performed on the thermistors to ensure that they meet the requirements of the humidity calibration facility. Different types of thermistors were evaluated up to , and the selected type showed a short-term drift of less than 2 mK. Exposure of these thermistors to temperatures up to gave an initial hysteresis of 40 mK, but after this initial hysteresis, the hysteresis, over the range from up to , was less than 10 mK. Use of a digital multimeter, with a low-power option, limited the self-heating of the thermistors, over the range from up to , to less than 5 mK. During use in the new setup, the thermistors were exposed to changing humidities between 1 %Rh and 90 %Rh and temperatures up to , showing drifts of less than 10 mK.

van Geel, J. L. W. A.; Bosma, R.; van Wensveen, J.; Peruzzi, A.

2015-03-01

483

The space simulation facilities at IAL SPACE  

NASA Technical Reports Server (NTRS)

The thermal vacuum facilities of IAL SPACE were tailored for testing of the ESA payloads. They were progressively upgraded for cryogenic payloads including 4 K (liquid helium temperature) experiments. A detailed review of the three vacuum chambers, ranging from 1.5 to 5 m diameter, is presented including the corresponding capabilities in the vacuum, thermal, and optical fields. The various aspects of cleanliness, product assurance, and quality control are also presented.

Henrist, M.; Cucchiaro, A.; Domken, I.; Macau, J. P.

1990-01-01

484

The New LOTIS Test Facility  

NASA Technical Reports Server (NTRS)

The Large Optical Test and Integration Site (LOTIS) at the Lockheed Martin Space Systems Company in Sunnyvale, CA is designed for the verification and testing of optical systems. The facility consists of an 88 foot temperature stabilized vacuum chamber that also functions as a class 10k vertical flow cleanroom. Many problems were encountered in the design and construction phases. The industry capability to build large chambers is very weak. Through many delays and extra engineering efforts, the final product is very good. With 11 Thermal Conditioning Units and precision RTD s, temperature is uniform and stable within 1oF, providing an ideal environment for precision optical testing. Within this chamber and atop an advanced micro-g vibration-isolation bench is the 6.5 meter diameter LOTIS Collimator and Scene Generator, LOTIS alignment and support equipment. The optical payloads are also placed on the vibration bench in the chamber for testing. This optical system is designed to operate in both air and vacuum, providing test imagery in an adaptable suite of visible/near infrared (VNIR) and midwave infrared (MWIR) point sources, and combined bandwidth visible-through-MWIR point sources, for testing of large aperture optical payloads. The heart of the system is the LOTIS Collimator, a 6.5m f/15 telescope, which projects scenes with wavefront errors <85 nm rms out to a 0.75 mrad field of view (FOV). Using field lenses, performance can be extended to a maximum field of view of 3.2 mrad. The LOTIS Collimator incorporates an extensive integrated wavefront sensing and control system to verify the performance of the system.

Bell, R. M.; Cuzner, G.; Eugeni, C.; Hutchison, S. B.; Merrick, A. J.; Robins, G. C.; Bailey, S. H.; Ceurden, B.; Hagen, J.; Kenagy, K.; Martin, H. M.; Tuell, M.; Ward, M.; West, S. C.

2008-01-01

485

The Holifield Heavy Ion Research Facility  

SciTech Connect

Development of the Holifield facility has continued with resulting improvements in the number of ion species provided, ion energy for tandem-only operations, and utilization efficiency. The Holifield Heavy Ion Research Facility (HHIRF) is located at the Oak Ridge National Laboratory and operated as a national user facility for research in heavy ion science. The facility operates two accelerators: an NEC pelletron tandem accelerator designed to operate at terminal potentials up to 25 MV and the Oak Ridge Isochronous Cyclotron (ORIC) which has been modified to serve as an energy booster for beams from the tandem accelerator. The principal experimental devices of the facility include a broad range spectrograph (ME/q/sup 2/ = 225) equipped with a vertical drift chamber detector system, a 4..pi.. spin spectrometer equipped with 72 NaI detectors (Ge detectors and BGO compton-suppression units can be used in place of the NaI detectors), a time-of-flight spectrometer, a 1.6-m scattering chamber, a heavy-ion/light-ion detector (HILI) which will be used for studying inverse reactions, a split-pole spectrograph, and a velocity filter. In this report, we will discuss our recent development activities, operational experience, and future development plans.

Jones, C.M.; Alton, G.D.; Ball, J.B.; Biggerstaff, J.A.; Dowling, D.T.; Erb, K.A.; Haynes, D.L.; Hoglund, D.E.; Hudson, E.D.; Juras, R.C.

1987-01-01

486

Long ion chamber systems for the SLC  

Microsoft Academic Search

A Panofsky Long Ion Chamber (PLIC) is essentially a gas-filled coaxial cable, and has been used to protect the Stanford Linear Accelerator from damage caused by its electron beam, and also as a sensitive diagnostic tool. This old technology has been updated and has found renewed use in the SLC. PLIC systems have been installed as beam-steering aids in most

J. Rolfe; R. Gearhart; R. Jacobsen; T. Jenkins; D. McComick; R. Nelson; D. Reagan; M. Ross

1989-01-01

487

Multiphysics Nuclear Thermal Rocket Thrust Chamber Analysis  

NASA Technical Reports Server (NTRS)

The objective of this effort is t o develop an efficient and accurate thermo-fluid computational methodology to predict environments for hypothetical thrust chamber design and analysis. The current task scope is to perform multidimensional, multiphysics analysis of thrust performance and heat transfer analysis for a hypothetical solid-core, nuclear thermal engine including thrust chamber and nozzle. The multiphysics aspects of the model include: real fluid dynamics, chemical reactivity, turbulent flow, and conjugate heat transfer. The model will be designed to identify thermal, fluid, and hydrogen environments in all flow paths and materials. This model would then be used to perform non- nuclear reproduction of the flow element failures demonstrated in the Rover/NERVA testing, investigate performance of specific configurations and assess potential issues and enhancements. A two-pronged approach will be employed in this effort: a detailed analysis of a multi-channel, flow-element, and global modeling of the entire thrust chamber assembly with a porosity modeling technique. It is expected that the detailed analysis of a single flow element would provide detailed fluid, thermal, and hydrogen environments for stress analysis, while the global thrust chamber assembly analysis would promote understanding of the effects of hydrogen dissociation and heat transfer on thrust performance. These modeling activities will be validated as much as possible by testing performed by other related efforts.

Wang, Ten-See

2005-01-01

488

HERL BIOLOGICAL EXPOSURE CHAMBER CONCEPTUAL DESIGN  

EPA Science Inventory

Because of the current interest in biotesting of potentially hazardous air pollutants, the Health Effects Research Laboratory (HERL) of EPA/RTP has contracted Radian to design biological exposure chambers that can be used to expose text organisms to the secondary aerosol effluent...

489

Recent Advances in Chamber Science and Technology  

E-print Network

Recent Advances in Chamber Science and Technology Mohamed Abdou April 8, 2002ISFNT-6 San Diego, USA;HYLIFE-II ALPS/APEX NSTX Li module Liquid Wall Science & Technology are being Advanced in Several MFE LM Wall (R.Woolley) - Adhesion to the wall by BJF ??? ?? Magnetic propulsion scheme (L

California at Los Angeles, University of

490

All-inorganic spark-chamber frame  

NASA Technical Reports Server (NTRS)

Outgassing is reduced by using ceramic and glass materials exclusively. Frames are assembled from four beams with rabbeted ends. Only ceramic or glass adhesives are used, and printed circuit is applied by screen printing directly on beams. Inorganic frames provide stable spark-chamber operation without gas refill, useful in terrestrial gamma-ray studies, in high-energy physics research, and other applications.

Heslin, T. M.

1980-01-01

491

PAINT COATINGS: CONTROLLED FIELD AND CHAMBER EXPERIMENTS  

EPA Science Inventory

To determine the impact of pollution levels on the weathering rates of coatings, laboratory chamber experiments and controlled field exposures at North Carolina and Ohio sites were conducted in such a manner to separate the contributions due to dry deposition, wet deposition, pre...

492

Experiments on a novel vapor chamber  

Microsoft Academic Search

A novel vapor chamber is proposed and tested in this study. Multi-layer copper mesh is sintered to the inner surface of the bottom plate as the evaporator wick. Parallel channels, with inter-channel openings, are made on the inner surface of the top plate. The peaks of the channel walls directly contact with the wick so that the channels function as

Shwin-Chung Wong; Jia-Da Wu; Wei-Lun Han

2008-01-01

493

Thirty-Six-Atmosphere Diffusion Cloud Chamber  

Microsoft Academic Search

A 36-atmosphere diffusion cloud chamber has been constructed for use with the 184-inch cyclotron and with the bevatron. Minimum-ionizing particles leave dense, sharp tracks of good contrast with hydrogen filling at design pressure. In the operation described, one event is obtained every 15 minutes for a reaction cross section of 30 mb for negative pions on hydrogen. Among the unique

John B. Elliott; George Maenchen; Peter H. Moulthrop; Larry O. Oswald; Wilson M. Powell; Robert W. Wright

1955-01-01

494

Ionization Chamber Bursts at High Altitudes  

Microsoft Academic Search

A thin-walled, low pressure ionization chamber has been sent into the upper atmosphere by means of balloons to study bursts of ionization. Pulse size, barometric pressure, and temperature were telemetered to the ground by means of a FM audio subcarrier system with a 75-Mc radio link. Measurements have been made of the size and frequency of bursts of ionization greater

Thomas Coor; T. Jr

1951-01-01

495

Chamber transport for heavy ion fusion  

NASA Astrophysics Data System (ADS)

A brief review is given of research on chamber transport for HIF (heavy ion fusion) dating from the first HIF Workshop in 1976 to the present. Chamber transport modes are categorized into ballistic transport modes and channel-like modes. Four major HIF reactor studies are summarized (HIBALL-II, HYLIFE-II, Prometheus-H, OSIRIS), with emphasis on the chamber transport environment. In general, many beams are used to provide the required symmetry and to permit focusing to the required small spots. Target parameters are then discussed, with a summary of the individual heavy ion beam parameters required for HIF. The beam parameters are then classified as to their line charge density and perveance, with special emphasis on the perveance limits for radial space charge spreading, for the space charge limiting current, and for the magnetic (Alfven) limiting current. The major experiments on ballistic transport (SFFE, Sabre beamlets, GAMBLE II, NTX, NDCX) are summarized, with specific reference to the axial electron trapping limit for charge neutralization. The major experiments on channel-like transport (GAMBLE II channel, GAMBLE II self-pinch, LBNL channels, GSI channels) are discussed. The status of current research on HIF chamber transport is summarized, and the value of future NDCX-II transport experiments for the future of HIF is noted.

Olson, Craig L.

2014-01-01

496

A very large area Micro Pixel Chamber  

Microsoft Academic Search

A Micro Pixel Chamber, called “?-PIC”, is a gaseous 2D imaging detector with a fine pixel electrode based on the Printed Circuit Board technology, and we developed it for the X\\/gamma-ray imaging and the tracking of the charged particles [A. Ochi, et al., Nucl. Instr. and Meth. A 478 (2002) 196; T. Nagayoshi, et al., Nucl. Instr. and Meth. A

A. Takada; K. Hattori; S. Kabuki; H. Kubo; K. Miuchi; T. Nagayoshi; H. Nishimura; Y. Okada; R. Orito; H. Sekiya; A. Takeda; T. Tanimori; K. Ueno

2007-01-01

497

Miniature reaction chamber and devices incorporating same  

DOEpatents

The present invention generally relates to miniaturized devices for carrying out and controlling chemical reactions and analyses. In particular, the present invention provides devices which have miniature temperature controlled reaction chambers for carrying out a variety of synthetic and diagnostic applications, such as PCR amplification, nucleic acid hybridization, chemical labeling, nucleic acid fragmentation and the like.

Mathies, Richard A. (Moraga, CA); Woolley, Adam T. (Albany, CA)

2000-10-17

498

A reusable prepositioned ATP reaction chamber  

NASA Technical Reports Server (NTRS)

Luminescence biometer detects presence of life by means of light-emitting chemical reaction of luciferin and luciferase with adenosine triphosphate (ATP) that occurs in all living cells. Amount of light in reaction chamber is measured to determine presence and extent of life.

Hoffman, D. G.

1972-01-01

499

An Improved Continuous Flow Diffusion Cloud Chamber  

Microsoft Academic Search

A slightly improved version of the continuous flow diffusion cloud chamber which has been described earlier (Hudson and Squires, 1973) has been rotated so that the plates are vertical instead of horizontal, the air flow remaining horizontal. Without other modification, its count agrees with that of the improved horizontal version to within about 1% over the supersaturation range 1.0-0.5%. The

James G. Hudson; Patrick Squires

1976-01-01

500

The Principles of Cloud-Chamber Technique  

NASA Astrophysics Data System (ADS)

Author's preface; 1. The condensation and growth of drops; 2. Ionization in cloud tracks; 3. The production and maintenance of supersaturation; 4. Operation and photography; 5. Counter control; 6. The technique of precision measurements; 7. Interpretation of cloud-chamber photographs; References; Index.

Wilson, J. G.

2014-06-01